Implicit bias and its relation to health disparities: a teaching program and survey of medical students.

Science.gov (United States)

Gonzalez, Cristina M; Kim, Mimi Y; Marantz, Paul R

2014-01-01

The varying treatment of different patients by the same physician are referred to as within provider disparities. These differences can contribute to health disparities and are thought to be the result of implicit bias due to unintentional, unconscious assumptions. The purpose is to describe an educational intervention addressing both health disparities and physician implicit bias and the results of a subsequent survey exploring medical students' attitudes and beliefs toward subconscious bias and health disparities. A single session within a larger required course was devoted to health disparities and the physician's potential to contribute to health disparities through implicit bias. Following the session the students were anonymously surveyed on their Implicit Association Test (IAT) results, their attitudes and experiences regarding the fairness of the health care system, and the potential impact of their own implicit bias. The students were categorized based on whether they disagreed ("deniers") or agreed ("accepters") with the statement "Unconscious bias might affect some of my clinical decisions or behaviors." Data analysis focused specifically on factors associated with this perspective. The survey response rate was at least 69%. Of the responders, 22% were "deniers" and 77% were "accepters." Demographics between the two groups were not significantly different. Deniers were significantly more likely than accepters to report IAT results with implicit preferences toward self, to believe the IAT is invalid, and to believe that doctors and the health system provide equal care to all and were less likely to report having directly observed inequitable care. The recognition of bias cannot be taught in a single session. Our experience supports the value of teaching medical students to recognize their own implicit biases and develop skills to overcome them in each patient encounter, and in making this instruction part of the compulsory, longitudinal undergraduate

Non-response bias in physical activity trend estimates

Directory of Open Access Journals (Sweden)

Bauman Adrian

2009-11-01

Full Text Available Abstract Background Increases in reported leisure time physical activity (PA and obesity have been observed in several countries. One hypothesis for these apparently contradictory trends is differential bias in estimates over time. The purpose of this short report is to examine the potential impact of changes in response rates over time on the prevalence of adequate PA in Canadian adults. Methods Participants were recruited in representative national telephone surveys of PA from 1995-2007. Differences in PA prevalence estimates between participants and those hard to reach were assessed using Student's t tests adjusted for multiple comparisons. Results The number of telephone calls required to reach and speak with someone in the household increased over time, as did the percentage of selected participants who initially refused during the first interview attempt. A higher prevalence of adequate PA was observed with 5-9 attempts to reach anyone in the household in 1999-2002, but this was not significant after adjustment for multiple comparisons. Conclusion No significant impact on PA trend estimates was observed due to differential non response rates. It is important for health policy makers to understand potential biases and how these may affect secular trends in all aspects of the energy balance equation.

Sources of Response Bias in Older Ethnic Minorities: A Case of Korean American Elderly

Science.gov (United States)

Kim, Miyong T.; Ko, Jisook; Yoon, Hyunwoo; Kim, Kim B.; Jang, Yuri

2015-01-01

The present study was undertaken to investigate potential sources of response bias in empirical research involving older ethnic minorities and to identify prudent strategies to reduce those biases, using Korean American elderly (KAE) as an example. Data were obtained from three independent studies of KAE (N=1,297; age ≥60) in three states (Florida, New York, and Maryland) from 2000 to 2008. Two common measures, Pearlin’s Mastery Scale and the CES-D scale, were selected for a series of psychometric tests based on classical measurement theory. Survey items were analyzed in depth, using psychometric properties generated from both exploratory factor analysis and confirmatory factor analysis as well as correlational analysis. Two types of potential sources of bias were identified as the most significant contributors to increases in error variances for these psychological instruments. Error variances were most prominent when (1) items were not presented in a manner that was culturally or contextually congruent with respect to the target population and/or (2) the response anchors for items were mixed (e.g., positive vs. negative). The systemic patterns and magnitudes of the biases were also cross-validated for the three studies. The results demonstrate sources and impacts of measurement biases in studies of older ethnic minorities. The identified response biases highlight the need for re-evaluation of current measurement practices, which are based on traditional recommendations that response anchors should be mixed or that the original wording of instruments should be rigidly followed. Specifically, systematic guidelines for accommodating cultural and contextual backgrounds into instrument design are warranted. PMID:26049971

Getting physicians to open the survey: little evidence that an envelope teaser increases response rates

Directory of Open Access Journals (Sweden)

Ziegenfuss Jeanette Y

2012-03-01

Full Text Available Abstract Background Physician surveys are an important tool to assess attitudes, beliefs and self-reported behaviors of this policy relevant group. In order for a physician to respond to a mailed survey, they must first open the envelope. While there is some evidence that package elements can impact physician response rates, the impact of an envelope teaser is unknown. Here we assess this by testing the impact of adding a brightly colored "$25 incentive" sticker to the outside of an envelope on response rates and nonresponse bias in a survey of physicians. Methods In the second mailing of a survey assessing physicians' moral beliefs and views on controversial health care topics, initial nonrespondents were randomly assigned to receive a survey in an envelope with a colored "$25 incentive" sticker (teaser group or an envelope without a sticker (control group. Response rates were compared between the teaser and control groups overall and by age, gender, region of the United States, specialty and years in practice. Nonresponse bias was assessed by comparing the demographic composition of the respondents to the nonrespondents in the experimental and control condition. Results No significant differences in response rates were observed between the experimental and control conditions overall (p = 0.38 or after stratifying by age, gender, region, or practice type. Within the teaser condition, there was some variation in response rate by years since graduation. There was no independent effect of the teaser on response when simultaneously controlling for demographic characteristics (OR = 0.875, p = 0.4112. Conclusions Neither response rates nor nonresponse bias were impacted by the use of an envelope teaser in a survey of physicians in the United States.

Cognitive Reflection, Decision Biases, and Response Times.

Science.gov (United States)

Alós-Ferrer, Carlos; Garagnani, Michele; Hügelschäfer, Sabine

2016-01-01

We present novel evidence on response times and personality traits in standard questions from the decision-making literature where responses are relatively slow (medians around half a minute or above). To this end, we measured response times in a number of incentivized, framed items (decisions from description) including the Cognitive Reflection Test, two additional questions following the same logic, and a number of classic questions used to study decision biases in probability judgments (base-rate neglect, the conjunction fallacy, and the ratio bias). All questions create a conflict between an intuitive process and more deliberative thinking. For each item, we then created a non-conflict version by either making the intuitive impulse correct (resulting in an alignment question), shutting it down (creating a neutral question), or making it dominant (creating a heuristic question). For CRT questions, the differences in response times are as predicted by dual-process theories, with alignment and heuristic variants leading to faster responses and neutral questions to slower responses than the original, conflict questions. For decision biases (where responses are slower), evidence is mixed. To explore the possible influence of personality factors on both choices and response times, we used standard personality scales including the Rational-Experiential Inventory and the Big Five, and used them as controls in regression analysis.

Gender anomalies in stated preference surveys – are biases really gender dependent?

DEFF Research Database (Denmark)

Ladenburg, Jacob; Olsen, Søren Bøye

2010-01-01

The potential for a number of common but severe biases in stated preference method surveys being gender dependent has been largely overlooked in the literature. In this paper we summarize results from three Choice Experiment studies that find evidence in favor of gender differences in vulnerability...... set up a novel theoretical model, which provides an explanation for gender specific susceptibility to biases. We conclude that biases can indeed be gender dependent. Hence, researchers should not simply disregard potential gender differences, but rather take them into account and examine the extent...... of them when performing surveys. Finally, we give suggestions for future research in this area....

Spectroscopic failures in photometric redshift calibration: cosmological biases and survey requirements

Energy Technology Data Exchange (ETDEWEB)

Cunha, Carlos E. [KIPAC, Menlo Park; Huterer, Dragan [Michigan U.; Lin, Huan [Fermilab; Busha, Michael T. [Zurich U.; Wechsler, Risa H. [SLAC

2014-10-11

We use N-body-spectro-photometric simulations to investigate the impact of incompleteness and incorrect redshifts in spectroscopic surveys to photometric redshift training and calibration and the resulting effects on cosmological parameter estimation from weak lensing shear-shear correlations. The photometry of the simulations is modeled after the upcoming Dark Energy Survey and the spectroscopy is based on a low/intermediate resolution spectrograph with wavelength coverage of 5500{\\AA} < {\\lambda} < 9500{\\AA}. The principal systematic errors that such a spectroscopic follow-up encounters are incompleteness (inability to obtain spectroscopic redshifts for certain galaxies) and wrong redshifts. Encouragingly, we find that a neural network-based approach can effectively describe the spectroscopic incompleteness in terms of the galaxies' colors, so that the spectroscopic selection can be applied to the photometric sample. Hence, we find that spectroscopic incompleteness yields no appreciable biases to cosmology, although the statistical constraints degrade somewhat because the photometric survey has to be culled to match the spectroscopic selection. Unfortunately, wrong redshifts have a more severe impact: the cosmological biases are intolerable if more than a percent of the spectroscopic redshifts are incorrect. Moreover, we find that incorrect redshifts can also substantially degrade the accuracy of training set based photo-z estimators. The main problem is the difficulty of obtaining redshifts, either spectroscopically or photometrically, for objects at z > 1.3. We discuss several approaches for reducing the cosmological biases, in particular finding that photo-z error estimators can reduce biases appreciably.

The impact of response bias on estimates of health care utilization in a metropolitan area: The use of administrative data

NARCIS (Netherlands)

Reijneveld, S.A.; Stronks, K.

1999-01-01

Background. Surveys among the general population are an important method for collecting epidemiological data on health and utilization of health care in that population. Selective non-response may affect the validity of these data. This study examines the impact of response bias on estimates of

[Potential selection bias in telephone surveys: landline and mobile phones].

Science.gov (United States)

Garcia-Continente, Xavier; Pérez-Giménez, Anna; López, María José; Nebot, Manel

2014-01-01

The increasing use of mobile phones in the last decade has decreased landline telephone coverage in Spanish households. This study aimed to analyze sociodemographic characteristics and health indicators by type of telephone service (mobile phone vs. landline or landline and mobile phone). Two telephone surveys were conducted in Spanish samples (February 2010 and February 2011). Multivariate logistic regression analyses were performed to analyze differences in the main sociodemographic characteristics and health indicators according to the type of telephone service available in Spanish households. We obtained 2027 valid responses (1627 landline telephones and 400 mobile phones). Persons contacted through a mobile phone were more likely to be a foreigner, to belong to the manual social class, to have a lower educational level, and to be a smoker than those contacted through a landline telephone. The profile of the population that has only a mobile phone differs from that with a landline telephone. Therefore, telephone surveys that exclude mobile phones could show a selection bias. Copyright © 2013 SESPAS. Published by Elsevier Espana. All rights reserved.

Bias in child maltreatment self-reports using interactive voice response (IVR).

Science.gov (United States)

Kepple, Nancy J; Freisthler, Bridget; Johnson-Motoyama, Michelle

2014-10-01

Few methods estimate the prevalence of child maltreatment in the general population due to concerns about socially desirable responding and mandated reporting laws. Innovative methods, such as interactive voice response (IVR), may obtain better estimates that address these concerns. This study examined the utility of interactive voice response (IVR) for child maltreatment behaviors by assessing differences between respondents who completed and did not complete a survey using IVR technology. A mixed-mode telephone survey was conducted in English and Spanish in 50 cities in California during 2009. Caregivers (n=3,023) self-reported abusive and neglectful parenting behaviors for a focal child under the age of 13 using computer-assisted telephone interviewing and IVR. We used hierarchical generalized linear models to compare survey completion by caregivers nested within cities for the full sample and age-specific ranges. For demographic characteristics, caregivers born in the United States were more likely to complete the survey when controlling for covariates. Parenting stress, provision of physical needs, and provision of supervisory needs were not associated with survey completion in the full multivariate model. For caregivers of children 0-4 years (n=838), those reporting they could often or always hear their child from another room had a higher likelihood of survey completion. The findings suggest IVR could prove to be useful for future surveys that aim to estimate abusive and/or neglectful parenting behaviors given the limited bias observed for demographic characteristics and problematic parenting behaviors. Further research should expand upon its utility to advance estimation rates. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bias analysis to improve monitoring an HIV epidemic and its response: approach and application to a survey of female sex workers in Iran.

Science.gov (United States)

Mirzazadeh, Ali; Mansournia, Mohammad-Ali; Nedjat, Saharnaz; Navadeh, Soodabeh; McFarland, Willi; Haghdoost, Ali Akbar; Mohammad, Kazem

2013-10-01

We present probabilistic and Bayesian techniques to correct for bias in categorical and numerical measures and empirically apply them to a recent survey of female sex workers (FSW) conducted in Iran. We used bias parameters from a previous validation study to correct estimates of behaviours reported by FSW. Monte-Carlo Sensitivity Analysis and Bayesian bias analysis produced point and simulation intervals (SI). The apparent and corrected prevalence differed by a minimum of 1% for the number of 'non-condom use sexual acts' (36.8% vs 35.8%) to a maximum of 33% for 'ever associated with a venue to sell sex' (35.5% vs 68.0%). The negative predictive value of the questionnaire for 'history of STI' and 'ever associated with a venue to sell sex' was 36.3% (95% SI 4.2% to 69.1%) and 46.9% (95% SI 6.3% to 79.1%), respectively. Bias-adjusted numerical measures of behaviours increased by 0.1 year for 'age at first sex act for money' to 1.5 for 'number of sexual contacts in last 7 days'. The 'true' estimates of most behaviours are considerably higher than those reported and the related SIs are wider than conventional CIs. Our analysis indicates the need for and applicability of bias analysis in surveys, particularly in stigmatised settings.

Colour vision and response bias in a coral reef fish.

Science.gov (United States)

Cheney, Karen L; Newport, Cait; McClure, Eva C; Marshall, N Justin

2013-08-01

Animals use coloured signals for a variety of communication purposes, including to attract potential mates, recognize individuals, defend territories and warn predators of secondary defences (aposematism). To understand the mechanisms that drive the evolution and design of such visual signals, it is important to understand the visual systems and potential response biases of signal receivers. Here, we provide raw data on the spectral capabilities of a coral reef fish, the Picasso triggerfish Rhinecanthus aculeatus, which is potentially trichromatic with three cone sensitivities of 413 nm (single cone), 480 nm (double cone, medium sensitivity) and 528 nm (double cone, long sensitivity), and a rod sensitivity of 498 nm. The ocular media have a 50% transmission cut off at 405 nm. Behavioural experiments confirmed colour vision over their spectral range; triggerfish were significantly more likely to choose coloured stimuli over grey distractors, irrespective of luminance. We then examined whether response biases existed towards coloured and patterned stimuli to provide insight into how visual signals - in particular, aposematic colouration - may evolve. Triggerfish showed a preferential foraging response bias to red and green stimuli, in contrast to blue and yellow, irrespective of pattern. There was no response bias to patterned over monochromatic non-patterned stimuli. A foraging response bias towards red in fish differs from that of avian predators, who often avoid red food items. Red is frequently associated with warning colouration in terrestrial environments (ladybirds, snakes, frogs), whilst blue is used in aquatic environments (blue-ringed octopus, nudibranchs); whether the design of warning (aposematic) displays is a cause or consequence of response biases is unclear.

Cognitive Reflection, Decision Biases, and Response Times

Directory of Open Access Journals (Sweden)

Carlos Alos-Ferrer

2016-09-01

Full Text Available We present novel evidence on decision times and personality traits in standard questions from the decision-making literature where responses are relatively slow (medians around half a minute or above. To this end, we measured decision times in a number of incentivized, framed items (decisions from description including the Cognitive Reflection Test, two additional questions following the same logic, and a number of classic questions used to study decision biases in probability judgments (base-rate neglect, the conjunction fallacy, and the ratio bias. All questions create a conflict between an intuitive process and more deliberative thinking. For each item, we then created a non-conflict version by either making the intuitive impulse correct (resulting in an alignment question, shutting it down (creating a neutral question, or making it dominant (creating a heuristic question. For CRT questions, the differences in decision times are as predicted by dual-process theories, with alignment and heuristic variants leading to faster responses and neutral questions to slower responses than the original, conflict questions. For decision biases (where responses are slower, evidence is mixed. To explore the possible influence of personality factors on both choices and decision times, we used standard personality scales including the Rational-Experiential Inventory and the Big Five, and used the mas controls in regression analysis.

REAL-TIME ANALYSIS AND SELECTION BIASES IN THE SUPERNOVA LEGACY SURVEY

International Nuclear Information System (INIS)

Perrett, K.; Conley, A.; Carlberg, R.; Balam, D.; Hook, I. M.; Sullivan, M.; Pritchet, C.; Astier, P.; Balland, C.; Guy, J.; Hardin, D.; Pain, R.; Regnault, N.; Basa, S.; Fouchez, D.; Howell, D. A.

2010-01-01

The Supernova Legacy Survey (SNLS) has produced a high-quality, homogeneous sample of Type Ia supernovae (SNe Ia) out to redshifts greater than z = 1. In its first four years of full operation (to 2007 June), the SNLS discovered more than 3000 transient candidates, 373 of which have been spectroscopically confirmed as SNe Ia. Use of these SNe Ia in precision cosmology critically depends on an analysis of the observational biases incurred in the SNLS survey due to the incomplete sampling of the underlying SN Ia population. This paper describes our real-time supernova detection and analysis procedures, and uses detailed Monte Carlo simulations to examine the effects of Malmquist bias and spectroscopic sampling. Such sampling effects are found to become apparent at z ∼ 0.6, with a significant shift in the average magnitude of the spectroscopically confirmed SN Ia sample toward brighter values for z ∼> 0.75. We describe our approach to correct for these selection biases in our three-year SNLS cosmological analysis (SNLS3) and present a breakdown of the systematic uncertainties involved.

Racial bias in neural empathic responses to pain.

Directory of Open Access Journals (Sweden)

Luis Sebastian Contreras-Huerta

Full Text Available Recent studies have shown that perceiving the pain of others activates brain regions in the observer associated with both somatosensory and affective-motivational aspects of pain, principally involving regions of the anterior cingulate and anterior insula cortex. The degree of these empathic neural responses is modulated by racial bias, such that stronger neural activation is elicited by observing pain in people of the same racial group compared with people of another racial group. The aim of the present study was to examine whether a more general social group category, other than race, could similarly modulate neural empathic responses and perhaps account for the apparent racial bias reported in previous studies. Using a minimal group paradigm, we assigned participants to one of two mixed-race teams. We use the term race to refer to the Chinese or Caucasian appearance of faces and whether the ethnic group represented was the same or different from the appearance of the participant' own face. Using fMRI, we measured neural empathic responses as participants observed members of their own group or other group, and members of their own race or other race, receiving either painful or non-painful touch. Participants showed clear group biases, with no significant effect of race, on behavioral measures of implicit (affective priming and explicit group identification. Neural responses to observed pain in the anterior cingulate cortex, insula cortex, and somatosensory areas showed significantly greater activation when observing pain in own-race compared with other-race individuals, with no significant effect of minimal groups. These results suggest that racial bias in neural empathic responses is not influenced by minimal forms of group categorization, despite the clear association participants showed with in-group more than out-group members. We suggest that race may be an automatic and unconscious mechanism that drives the initial neural responses to

Racial Bias in Neural Empathic Responses to Pain

Science.gov (United States)

Contreras-Huerta, Luis Sebastian; Baker, Katharine S.; Reynolds, Katherine J.; Batalha, Luisa; Cunnington, Ross

2013-01-01

Recent studies have shown that perceiving the pain of others activates brain regions in the observer associated with both somatosensory and affective-motivational aspects of pain, principally involving regions of the anterior cingulate and anterior insula cortex. The degree of these empathic neural responses is modulated by racial bias, such that stronger neural activation is elicited by observing pain in people of the same racial group compared with people of another racial group. The aim of the present study was to examine whether a more general social group category, other than race, could similarly modulate neural empathic responses and perhaps account for the apparent racial bias reported in previous studies. Using a minimal group paradigm, we assigned participants to one of two mixed-race teams. We use the term race to refer to the Chinese or Caucasian appearance of faces and whether the ethnic group represented was the same or different from the appearance of the participant' own face. Using fMRI, we measured neural empathic responses as participants observed members of their own group or other group, and members of their own race or other race, receiving either painful or non-painful touch. Participants showed clear group biases, with no significant effect of race, on behavioral measures of implicit (affective priming) and explicit group identification. Neural responses to observed pain in the anterior cingulate cortex, insula cortex, and somatosensory areas showed significantly greater activation when observing pain in own-race compared with other-race individuals, with no significant effect of minimal groups. These results suggest that racial bias in neural empathic responses is not influenced by minimal forms of group categorization, despite the clear association participants showed with in-group more than out-group members. We suggest that race may be an automatic and unconscious mechanism that drives the initial neural responses to observed pain in

Evidence for Response Bias as a Source of Error Variance in Applied Assessment

Science.gov (United States)

McGrath, Robert E.; Mitchell, Matthew; Kim, Brian H.; Hough, Leaetta

2010-01-01

After 100 years of discussion, response bias remains a controversial topic in psychological measurement. The use of bias indicators in applied assessment is predicated on the assumptions that (a) response bias suppresses or moderates the criterion-related validity of substantive psychological indicators and (b) bias indicators are capable of…

Comparison of Self-Reported Telephone Interviewing and Web-Based Survey Responses: Findings From the Second Australian Young and Well National Survey

Science.gov (United States)

Davenport, Tracey A; Burns, Jane M; Hickie, Ian B

2017-01-01

analysis showed respondents who were male (beta=−.19, P=.048) or who were not in employment, education, or training (NEET; beta=−.32, P=.001) were significantly more likely to provide different responses on matched items when responding in the CATI as compared with the Web-based self-report survey. The Web-based self-report survey, however, demonstrated some evidence of avidity and attrition bias. Conclusions Compared with CATI, Web-based self-report surveys are highly cost-effective and had higher rates of self-disclosure on sensitive items, particularly for respondents who identify as male and NEET. A drawback to Web-based surveying methodologies, however, includes the limited control over avidity bias and the greater incidence of attrition bias. These findings have important implications for further development of survey methods in the area of health and well-being, especially when considering research topics (in this case diagnosis, suicidal ideation, sexting, and body image) and groups that are being recruited (young people, males, and NEET). PMID:28951382

Comparison of Self-Reported Telephone Interviewing and Web-Based Survey Responses: Findings From the Second Australian Young and Well National Survey.

Science.gov (United States)

Milton, Alyssa C; Ellis, Louise A; Davenport, Tracey A; Burns, Jane M; Hickie, Ian B

2017-09-26

(beta=-.19, P=.048) or who were not in employment, education, or training (NEET; beta=-.32, P=.001) were significantly more likely to provide different responses on matched items when responding in the CATI as compared with the Web-based self-report survey. The Web-based self-report survey, however, demonstrated some evidence of avidity and attrition bias. Compared with CATI, Web-based self-report surveys are highly cost-effective and had higher rates of self-disclosure on sensitive items, particularly for respondents who identify as male and NEET. A drawback to Web-based surveying methodologies, however, includes the limited control over avidity bias and the greater incidence of attrition bias. These findings have important implications for further development of survey methods in the area of health and well-being, especially when considering research topics (in this case diagnosis, suicidal ideation, sexting, and body image) and groups that are being recruited (young people, males, and NEET). ©Alyssa C Milton, Louise A Ellis, Tracey A Davenport, Jane M Burns, Ian B Hickie. Originally published in JMIR Mental Health (http://mental.jmir.org), 26.09.2017.

Gender-bias primes elicit queen-bee responses among senior policewomen.

Science.gov (United States)

Derks, Belle; Van Laar, Colette; Ellemers, Naomi; de Groot, Kim

2011-10-01

Queen bees are senior women in male-dominated organizations who have achieved success by emphasizing how they differ from other women. Although the behavior of queen bees tends to be seen as contributing to gender disparities in career outcomes, we argue that queen-bee behavior is actually a result of the gender bias and social identity threat that produce gender disparities in career outcomes. In the experiment reported here, we asked separate groups of senior policewomen to recall the presence or absence of gender bias during their careers, and we measured queen-bee responses (i.e., masculine self-descriptions, in-group distancing, and denying of discrimination). Such gender-bias priming increased queen-bee responses among policewomen with low gender identification, but policewomen with high gender identification responded with increased motivation to improve opportunities for other women. These results suggest that gender-biased work environments shape women's behavior by stimulating women with low gender identification to dissociate with other women and to display queen-bee responses as a way to achieve individual mobility.

Overview about bias in Customer Satisfaction Surveys and focus on self-selection error

OpenAIRE

Giovanna Nicolini; Luciana Dalla Valle

2009-01-01

The present paper provides an overview of the main types of surveys carried out for customer satisfaction analyses. In order to carry out these surveys it is possible to plan a census or select a sample. The higher the accuracy of the survey, the more reliable the results of the analysis. For this very reason, researchers pay special attention to surveys with bias due to non sampling errors, in particular to self-selection errors. These phenomena are very frequent especially in web surveys. S...

Can health workers reliably assess their own work? A test-retest study of bias among data collectors conducting a Lot Quality Assurance Sampling survey in Uganda.

Science.gov (United States)

Beckworth, Colin A; Davis, Rosemary H; Faragher, Brian; Valadez, Joseph J

2015-03-01

Lot Quality Assurance Sampling (LQAS) is a classification method that enables local health staff to assess health programmes for which they are responsible. While LQAS has been favourably reviewed by the World Bank and World Health Organization (WHO), questions remain about whether using local health staff as data collectors can lead to biased data. In this test-retest research, Pallisa Health District in Uganda is subdivided into four administrative units called supervision areas (SA). Data collectors from each SA conducted an LQAS survey. A week later, the data collectors were swapped to a different SA, outside their area of responsibility, to repeat the LQAS survey with the same respondents. The two data sets were analysed for agreement using Cohens' kappa coefficient and disagreements were analysed. Kappa values ranged from 0.19 to 0.97. On average, there was a moderate degree of agreement for knowledge indicators and a substantial level for practice indicators. Respondents were found to be systematically more knowledgeable on retest indicating bias favouring the retest, although no evidence of bias was found for practices indicators. In this initial study, using local health care providers to collect data did not bias data collection. The bias observed in the knowledge indicators is most likely due to the 'practice effect', whereby respondents increased their knowledge as a result of completing the first survey, as no corresponding effect was seen in the practices indicators. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine © The Author 2014; all rights reserved.

The impact of non-response bias due to sampling in public health studies: A comparison of voluntary versus mandatory recruitment in a Dutch national survey on adolescent health.

Science.gov (United States)

Cheung, Kei Long; Ten Klooster, Peter M; Smit, Cees; de Vries, Hein; Pieterse, Marcel E

2017-03-23

In public health monitoring of young people it is critical to understand the effects of selective non-response, in particular when a controversial topic is involved like substance abuse or sexual behaviour. Research that is dependent upon voluntary subject participation is particularly vulnerable to sampling bias. As respondents whose participation is hardest to elicit on a voluntary basis are also more likely to report risk behaviour, this potentially leads to underestimation of risk factor prevalence. Inviting adolescents to participate in a home-sent postal survey is a typical voluntary recruitment strategy with high non-response, as opposed to mandatory participation during school time. This study examines the extent to which prevalence estimates of adolescent health-related characteristics are biased due to different sampling methods, and whether this also biases within-subject analyses. Cross-sectional datasets collected in 2011 in Twente and IJsselland, two similar and adjacent regions in the Netherlands, were used. In total, 9360 youngsters in a mandatory sample (Twente) and 1952 youngsters in a voluntary sample (IJsselland) participated in the study. To test whether the samples differed on health-related variables, we conducted both univariate and multivariable logistic regression analyses controlling for any demographic difference between the samples. Additional multivariable logistic regressions were conducted to examine moderating effects of sampling method on associations between health-related variables. As expected, females, older individuals, as well as individuals with higher education levels, were over-represented in the voluntary sample, compared to the mandatory sample. Respondents in the voluntary sample tended to smoke less, consume less alcohol (ever, lifetime, and past four weeks), have better mental health, have better subjective health status, have more positive school experiences and have less sexual intercourse than respondents in the

Bias correction in species distribution models: pooling survey and collection data for multiple species.

Science.gov (United States)

Fithian, William; Elith, Jane; Hastie, Trevor; Keith, David A

2015-04-01

Presence-only records may provide data on the distributions of rare species, but commonly suffer from large, unknown biases due to their typically haphazard collection schemes. Presence-absence or count data collected in systematic, planned surveys are more reliable but typically less abundant.We proposed a probabilistic model to allow for joint analysis of presence-only and survey data to exploit their complementary strengths. Our method pools presence-only and presence-absence data for many species and maximizes a joint likelihood, simultaneously estimating and adjusting for the sampling bias affecting the presence-only data. By assuming that the sampling bias is the same for all species, we can borrow strength across species to efficiently estimate the bias and improve our inference from presence-only data.We evaluate our model's performance on data for 36 eucalypt species in south-eastern Australia. We find that presence-only records exhibit a strong sampling bias towards the coast and towards Sydney, the largest city. Our data-pooling technique substantially improves the out-of-sample predictive performance of our model when the amount of available presence-absence data for a given species is scarceIf we have only presence-only data and no presence-absence data for a given species, but both types of data for several other species that suffer from the same spatial sampling bias, then our method can obtain an unbiased estimate of the first species' geographic range.

Using hidden Markov models to deal with availability bias on line transect surveys.

Science.gov (United States)

Borchers, D L; Zucchini, W; Heide-Jørgensen, M P; Cañadas, A; Langrock, R

2013-09-01

We develop estimators for line transect surveys of animals that are stochastically unavailable for detection while within detection range. The detection process is formulated as a hidden Markov model with a binary state-dependent observation model that depends on both perpendicular and forward distances. This provides a parametric method of dealing with availability bias when estimates of availability process parameters are available even if series of availability events themselves are not. We apply the estimators to an aerial and a shipboard survey of whales, and investigate their properties by simulation. They are shown to be more general and more flexible than existing estimators based on parametric models of the availability process. We also find that methods using availability correction factors can be very biased when surveys are not close to being instantaneous, as can estimators that assume temporal independence in availability when there is temporal dependence. © 2013, The International Biometric Society.

Simultaneous perceptual and response biases on sequential face attractiveness judgments

Science.gov (United States)

Pegors, Teresa K.; Mattar, Marcelo G.; Bryan, Peter B.; Epstein, Russell A.

2015-01-01

Face attractiveness is a social characteristic that we often use to make first-pass judgments about the people around us. However, these judgments are highly influenced by our surrounding social world, and researchers still understand little about the mechanisms underlying these influences. In a series of three experiments, we used a novel sequential rating paradigm that enabled us to measure biases on attractiveness judgments from the previous face and the previous rating. Our results revealed two simultaneous and opposing influences on face attractiveness judgments that arise from our past experience of faces: a response bias in which attractiveness ratings shift towards a previously given rating, and a stimulus bias in which attractiveness ratings shift away from the mean attractiveness of the previous face. Furthermore, we provide evidence that the contrastive stimulus bias (but not the assimilative response bias) is strengthened by increasing the duration of the previous stimulus, suggesting an underlying perceptual mechanism. These results demonstrate that judgments of face attractiveness are influenced by information from our evaluative and perceptual history and that these influences have measurable behavioral effects over the course of just a few seconds. PMID:25867223

What we don't know can hurt us: Nonresponse bias assessment in birth defects research.

Science.gov (United States)

Strassle, Paula D; Cassell, Cynthia H; Shapira, Stuart K; Tinker, Sarah C; Meyer, Robert E; Grosse, Scott D

2015-07-01

Nonresponse bias assessment is an important and underutilized tool in survey research to assess potential bias due to incomplete participation. This study illustrates a nonresponse bias sensitivity assessment using a survey on perceived barriers to care for children with orofacial clefts in North Carolina. Children born in North Carolina between 2001 and 2004 with an orofacial cleft were eligible for inclusion. Vital statistics data, including maternal and child characteristics, were available on all eligible subjects. Missing 'responses' from nonparticipants were imputed using assumptions based on the distribution of responses, survey method (mail or phone), and participant maternal demographics. Overall, 245 of 475 subjects (51.6%) responded to either a mail or phone survey. Cost as a barrier to care was reported by 25.0% of participants. When stratified by survey type, 28.3% of mail respondents and 17.2% of phone respondents reported cost as a barrier. Under various assumptions, the bias-adjusted estimated prevalence of cost as barrier to care ranged from 16.1% to 30.0%. Maternal age, education, race, and marital status at time of birth were not associated with subjects reporting cost as a barrier. As survey response rates continue to decline, the importance of assessing the potential impact of nonresponse bias has become more critical. Birth defects research is particularly conducive to nonresponse bias analysis, especially when birth defect registries and birth certificate records are used. Future birth defect studies which use population-based surveillance data and have incomplete participation could benefit from this type of nonresponse bias assessment. Birth Defects Research (Part A) 103:603-609, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

The usefulness of the Basic Question Procedure for determining non-response bias in substantive variables - A test of four telephone questionnaires

NARCIS (Netherlands)

van Goor, H.; van Goor, A.

2007-01-01

The Basic Question Procedure (BQP) is a method for determining non-response bias. The BQP involves asking one basic question - that is, the question relating to the central substantive variable of the study - of those persons who refuse to participate in the survey. We studied the usefulness of this

Adjusting forest density estimates for surveyor bias in historical tree surveys

Science.gov (United States)

Brice B. Hanberry; Jian Yang; John M. Kabrick; Hong S. He

2012-01-01

The U.S. General Land Office surveys, conducted between the late 1700s to early 1900s, provide records of trees prior to widespread European and American colonial settlement. However, potential and documented surveyor bias raises questions about the reliability of historical tree density estimates and other metrics based on density estimated from these records. In this...

Bias Errors due to Leakage Effects When Estimating Frequency Response Functions

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Andreas Josefsson

2012-01-01

Full Text Available Frequency response functions are often utilized to characterize a system's dynamic response. For a wide range of engineering applications, it is desirable to determine frequency response functions for a system under stochastic excitation. In practice, the measurement data is contaminated by noise and some form of averaging is needed in order to obtain a consistent estimator. With Welch's method, the discrete Fourier transform is used and the data is segmented into smaller blocks so that averaging can be performed when estimating the spectrum. However, this segmentation introduces leakage effects. As a result, the estimated frequency response function suffers from both systematic (bias and random errors due to leakage. In this paper the bias error in the H1 and H2-estimate is studied and a new method is proposed to derive an approximate expression for the relative bias error at the resonance frequency with different window functions. The method is based on using a sum of real exponentials to describe the window's deterministic autocorrelation function. Simple expressions are derived for a rectangular window and a Hanning window. The theoretical expressions are verified with numerical simulations and a very good agreement is found between the results from the proposed bias expressions and the empirical results.

Comparison of the linear bias models in the light of the Dark Energy Survey

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Papageorgiou, A.; Basilakos, S.; Plionis, M.

2018-05-01

The evolution of the linear and scale independent bias, based on the most popular dark matter bias models within the Λ cold dark matter (ΛCDM) cosmology, is confronted to that of the Dark Energy Survey (DES) luminous red galaxies (LRGs). Applying a χ2 minimization procedure between models and data, we find that all the considered linear bias models reproduce well the LRG bias data. The differences among the bias models are absorbed in the predicted mass of the dark-matter halo in which LRGs live and which ranges between ˜6 × 1012 and 1.4 × 1013 h-1 M⊙, for the different bias models. Similar results, reaching however a maximum value of ˜2 × 1013 h-1 M⊙, are found by confronting the SDSS (2SLAQ) Large Red Galaxies clustering with theoretical clustering models, which also include the evolution of bias. This later analysis also provides a value of Ωm = 0.30 ± 0.01, which is in excellent agreement with recent joint analyses of different cosmological probes and the reanalysis of the Planck data.

The Effects of Halo Assembly Bias on Self-Calibration in Galaxy Cluster Surveys

Energy Technology Data Exchange (ETDEWEB)

Wu, Hao-Yi; Rozo, Eduardo; Wechsler, Risa H.

2008-08-07

Self-calibration techniques for analyzing galaxy cluster counts utilize the abundance and the clustering amplitude of dark matter halos. These properties simultaneously constrain cosmological parameters and the cluster observable-mass relation. It was recently discovered that the clustering amplitude of halos depends not only on the halo mass, but also on various secondary variables, such as the halo formation time and the concentration; these dependences are collectively termed 'assembly bias'. Applying modified Fisher matrix formalism, we explore whether these secondary variables have a significant impact on the study of dark energy properties using the self-calibration technique in current (SDSS) and the near future (DES, SPT, and LSST) cluster surveys. The impact of the secondary dependence is determined by (1) the scatter in the observable-mass relation and (2) the correlation between observable and secondary variables. We find that for optical surveys, the secondary dependence does not significantly influence an SDSS-like survey; however, it may affect a DES-like survey (given the high scatter currently expected from optical clusters) and an LSST-like survey (even for low scatter values and low correlations). For an SZ survey such as SPT, the impact of secondary dependence is insignificant if the scatter is 20% or lower but can be enhanced by the potential high scatter values introduced by a highly-correlated background. Accurate modeling of the assembly bias is necessary for cluster self-calibration in the era of precision cosmology.

The Response Dynamics of Recognition Memory: Sensitivity and Bias

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Koop, Gregory J.; Criss, Amy H.

2016-01-01

Advances in theories of memory are hampered by insufficient metrics for measuring memory. The goal of this paper is to further the development of model-independent, sensitive empirical measures of the recognition decision process. We evaluate whether metrics from continuous mouse tracking, or response dynamics, uniquely identify response bias and…

Mood-congruent free recall bias in anxious individuals is not a consequence of response bias.

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Russo, Riccardo; Whittuck, Dora; Roberson, Debi; Dutton, Kevin; Georgiou, George; Fox, Elaine

2006-05-01

The status of mood-congruent free recall bias in anxious individuals was evaluated following incidental encoding of target words. Individuals with high and low levels of trait anxiety completed a modified Stroop task, which revealed an attentional bias for threat-related stimuli in anxious individuals. This group was significantly slower in naming the colour in which threat-related words were displayed compared to neutral words. In a subsequent free recall test for the words used in the modified Stroop task, anxious individuals recalled more threat-related words compared to low-anxious people. This difference was significant even when controlling for the false recall of items that had not been presented during study. These results support the view put forward by Russo, Fox, Bellinger, and Nguyen-Van-Tam (2001) that mood-congruent free recall bias in anxious individuals can be observed if the target material is encoded at a relatively shallow level. Moreover, contrary to Dowens and Calvo (2003), the current results show that the memory advantage for threat-related information in anxious individuals is not a consequence of response bias.

Analysis of bias effects on the total ionizing dose response in a 180 nm technology

International Nuclear Information System (INIS)

Liu Zhangli; Hu Zhiyuan; Zhang, Zhengxuan; Shao Hua; Chen Ming; Bi Dawei; Ning Bingxu; Zou Shichang

2011-01-01

The effects of gamma ray irradiation on the shallow trench isolation (STI) leakage current in a 180 nm technology are investigated. The radiation response is strongly influenced by the bias modes, gate bias during irradiation, substrate bias during irradiation and operating substrate bias after irradiation. We found that the worst case occurs under the ON bias condition for the ON, OFF and PASS bias mode. A positive gate bias during irradiation significantly enhances the STI leakage current, indicating the electric field influence on the charge buildup process during radiation. Also, a negative substrate bias during irradiation enhances the STI leakage current. However a negative operating substrate bias effectively suppresses the STI leakage current, and can be used to eliminate the leakage current produced by the charge trapped in the deep STI oxide. Appropriate substrate bias should be introduced to alleviate the total ionizing dose (TID) response, and lead to acceptable threshold voltage shift and subthreshold hump effect. Depending on the simulation results, we believe that the electric field distribution in the STI oxide is the key parameter influencing bias effects on the radiation response of transistor. - Highlights: → ON bias is the worst bias condition for the ON, PASS and OFF bias modes. → Larger gate bias during irradiation leads to more pronounced characteristic degradation. → TID induced STI leakage can be suppressed by negative operating substrate bias voltage. → Negative substrate bias during irradiation leads to larger increase of off-state leakage. → Electric field in the STI oxide greatly influences the device's radiation effect.

Development and Validation of a Response Bias Scale (RBS) for the MMPI-2

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Gervais, Roger O.; Ben-Porath, Yossef S.; Wygant, Dustin B.; Green, Paul

2007-01-01

This study describes the development of a Minnesota Multiphasic Personality Inventory (MMPI-2) scale designed to detect negative response bias in forensic neuropsychological or disability assessment settings. The Response Bias Scale (RBS) consists of 28 MMPI-2 items that discriminated between persons who passed or failed the Word Memory Test…

Social Desirability, Non-Response Bias and Reliability in a Long Self-Report Measure: Illustrations from the MMPI-2 Administered to Brunei Student Teachers

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Mundia, Lawrence

2011-01-01

The survey investigated the problems of social desirability (SD), non-response bias (NRB) and reliability in the Minnesota Multiphasic Personality Inventory--Revised (MMPI-2) self-report inventory administered to Brunei student teachers. Bruneians scored higher on all the validity scales than the normative US sample, thereby threatening the…

[Study on correction of data bias caused by different missing mechanisms in survey of medical expenditure among students enrolling in Urban Resident Basic Medical Insurance].

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Zhang, Haixia; Zhao, Junkang; Gu, Caijiao; Cui, Yan; Rong, Huiying; Meng, Fanlong; Wang, Tong

2015-05-01

The study of the medical expenditure and its influencing factors among the students enrolling in Urban Resident Basic Medical Insurance (URBMI) in Taiyuan indicated that non response bias and selection bias coexist in dependent variable of the survey data. Unlike previous studies only focused on one missing mechanism, a two-stage method to deal with two missing mechanisms simultaneously was suggested in this study, combining multiple imputation with sample selection model. A total of 1 190 questionnaires were returned by the students (or their parents) selected in child care settings, schools and universities in Taiyuan by stratified cluster random sampling in 2012. In the returned questionnaires, 2.52% existed not missing at random (NMAR) of dependent variable and 7.14% existed missing at random (MAR) of dependent variable. First, multiple imputation was conducted for MAR by using completed data, then sample selection model was used to correct NMAR in multiple imputation, and a multi influencing factor analysis model was established. Based on 1 000 times resampling, the best scheme of filling the random missing values is the predictive mean matching (PMM) method under the missing proportion. With this optimal scheme, a two stage survey was conducted. Finally, it was found that the influencing factors on annual medical expenditure among the students enrolling in URBMI in Taiyuan included population group, annual household gross income, affordability of medical insurance expenditure, chronic disease, seeking medical care in hospital, seeking medical care in community health center or private clinic, hospitalization, hospitalization canceled due to certain reason, self medication and acceptable proportion of self-paid medical expenditure. The two-stage method combining multiple imputation with sample selection model can deal with non response bias and selection bias effectively in dependent variable of the survey data.

Estimating low-bias frequency response using random decrement

DEFF Research Database (Denmark)

Brincker, Rune; Brandt, Anders

2011-01-01

It is well known that in order to minimize the influence of leakage bias in frequency response function (FRF) estimates, smooth windows should be applied in the FFT processing. It is also normal practice to use self windowing excitation signals whenever possible. However, in many cases FRFs have...

The negativity bias predicts response rate to Behavioral Activation for depression.

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Gollan, Jackie K; Hoxha, Denada; Hunnicutt-Ferguson, Kallio; Norris, Catherine J; Rosebrock, Laina; Sankin, Lindsey; Cacioppo, John

2016-09-01

This treatment study investigated the extent to which asymmetric dimensions of affective responding, specifically the positivity offset and the negativity bias, at pretreatment altered the rate of response to Behavioral Activation treatment for depression. Forty-one depressed participants were enrolled into 16 weekly sessions of BA. An additional 36 lifetime healthy participants were evaluated prospectively for 16 weeks to compare affective responding between healthy and remitted patients at post-treatment. All participants were assessed at Weeks 0, 8 and 16 using repeated measures, involving a structured clinical interview for DSM-IV Axis I disorders, questionnaires, and a computerized task designed to measure affective responses to unpleasant, neutral, and pleasant images. The negativity bias at pre-treatment predicted the rate of response to BA, while the positivity offset did not. Only one treatment condition was used in this study and untreated depressed participants were not enrolled, limiting our ability to compare the effect of BA. Baseline negativity bias may serve as a signal for patients to engage in and benefit from the goal-directed BA strategies, thereby accelerating rate of response. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identifying Pertinent Variables for Nonresponse Follow-Up Surveys. Lessons Learned from 4 Cases in Switzerland

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Caroline Vandenplas

2015-12-01

Full Text Available All social surveys suffer from different types of errors, of which one of the most studied is non-response bias. Non-response bias is a systematic error that occurs because individuals differ in their accessibility and propensity to participate in a survey according to their own characteristics as well as those from the survey itself. The extent of the problem heavily depends on the correlation between response mechanisms and key survey variables. However, non-response bias is difficult to measure or to correct for due to the lack of relevant data about the whole target population or sample. In this paper, non-response follow-up surveys are considered as a possible source of information about non-respondents. Non-response follow-ups, however, suffer from two methodological issues: they themselves operate through a response mechanism that can cause potential non-response bias, and they pose a problem of comparability of measure, mostly because the survey design differs between main survey and non-response follow-up. In order to detect possible bias, the survey variables included in non-response surveys have to be related to the mechanism of participation, but not be sensitive to measurement effects due to the different designs. Based on accumulated experience of four similar non-response follow-ups, we studied the survey variables that fulfill these conditions. We differentiated socio-demographic variables that are measurement-invariant but have a lower correlation with non-response and variables that measure attitudes, such as trust, social participation, or integration in the public sphere, which are more sensitive to measurement effects but potentially more appropriate to account for the non-response mechanism. Our results show that education level, work status, and living alone, as well as political interest, satisfaction with democracy, and trust in institutions are pertinent variables to include in non-response follow-ups of general social

[Retrospective analysis of Mexican National Addictions Survey, 2008. Bias identification and correction].

Science.gov (United States)

Romero-Martínez, Martín; Téllez-Rojo Solís, Martha María; Sandoval-Zárate, América Andrea; Zurita-Luna, Juan Manuel; Gutiérrez-Reyes, Juan Pablo

2013-01-01

To determine the presence of bias on the estimation of the consumption sometime in life of alcohol, tobacco or illegal drugs and inhalable substances, and to propose a correction for this in the case it is present. Mexican National Addictions Surveys (NAS) 2002, 2008, and 2011 were analyzed to compare population estimations of consumption sometime in life of tobacco, alcohol or illegal drugs and inhalable substances. A couple of alternative approaches for bias correction were developed. Estimated national prevalences of consumption sometime in life of alcohol and tobacco in the NAS 2008 are not plausible. There was no evidence of bias on the consumption sometime in life of illegal drugs and inhalable substances. New estimations for tobacco and alcohol consumption sometime in life were made, which resulted in plausible values when compared to other data available. Future analyses regarding tobacco and alcohol using NAS 2008 data will have to rely on these newly generated data weights, that are able to reproduce the new (plausible) estimations.

Voluntary vs. compulsory student evaluation of clerkships: effect on validity and potential bias.

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Aoun Bahous, Sola; Salameh, Pascale; Salloum, Angelique; Salameh, Wael; Park, Yoon Soo; Tekian, Ara

2018-01-05

Students evaluations of their learning experiences can provide a useful source of information about clerkship effectiveness in undergraduate medical education. However, low response rates in clerkship evaluation surveys remain an important limitation. This study examined the impact of increasing response rates using a compulsory approach on validity evidence. Data included 192 responses obtained voluntarily from 49 third-year students in 2014-2015, and 171 responses obtained compulsorily from 49 students in the first six months of the consecutive year at one medical school in Lebanon. Evidence supporting internal structure and response process validity was compared between the two administration modalities. The authors also tested for potential bias introduced by the use of the compulsory approach by examining students' responses to a sham item that was added to the last survey administration. Response rates increased from 56% in the voluntary group to 100% in the compulsory group (P two consecutive years. Testing for non-response bias in the voluntary group showed that females were more frequent responders in two clerkships. Testing for authority-induced bias revealed that students might complete the evaluation randomly without attention to content. While increasing response rates is often a policy requirement aimed to improve the credibility of ratings, using authority to enforce responses may not increase reliability and can raise concerns over the meaningfulness of the evaluation. Administrators are urged to consider not only response rates, but also representativeness and quality of responses in administering evaluation surveys.

The effect of non-response on estimates of health care utilisation

DEFF Research Database (Denmark)

Gundgaard, Jens; Ekholm, Orla; Hansen, Ebba Holme

2008-01-01

BACKGROUND: Non-response in health surveys may lead to bias in estimates of health care utilisation. The magnitude, direction and composition of the bias are usually not well known. When data from health surveys are merged with data from registers at the individual level, analyses can reveal non......-response bias. Our aim was to estimate the composition, direction and magnitude of non-response bias in the estimation of health care costs in two types of health interview surveys. METHODS: The surveys were (1) a national personal interview survey of 22 484 Danes (2) a telephone interview survey of 5000 Danes...... living in Funen County. Data were linked with register information on health care utilisation in hospitals and primary care. Health care utilisation was estimated for respondents and non-respondents, and the difference was explained by a decomposition method of bias components. RESULTS: The surveys...

Interpretation bias and social anxiety: does interpretation bias mediate the relationship between trait social anxiety and state anxiety responses?

Science.gov (United States)

Chen, Junwen; Milne, Kirby; Dayman, Janet; Kemps, Eva

2018-05-23

Two studies aimed to examine whether high socially anxious individuals are more likely to negatively interpret ambiguous social scenarios and facial expressions compared to low socially anxious individuals. We also examined whether interpretation bias serves as a mediator of the relationship between trait social anxiety and state anxiety responses, in particular current state anxiety, bodily sensations, and perceived probability and cost of negative evaluation pertaining to a speech task. Study 1 used ambiguous social scenarios and Study 2 used ambiguous facial expressions as stimuli to objectively assess interpretation bias. Undergraduate students with high and low social anxiety completed measures of state anxiety responses at three time points: baseline, after the interpretation bias task, and after the preparation for an impromptu speech. Results showed that high socially anxious individuals were more likely to endorse threat interpretations for ambiguous social scenarios and to interpret ambiguous faces as negative than low socially anxious individuals. Furthermore, negative interpretations mediated the relationship between trait social anxiety and perceived probability of negative evaluation pertaining to the speech task in Study 1 but not Study 2. The present studies provide new insight into the role of interpretation bias in social anxiety.

Retrospective analysis of Mexican National Addictions Survey, 2008. Bias identification and correction.

Directory of Open Access Journals (Sweden)

Martín Romero-Martínez

2013-05-01

Full Text Available Objective. To determine the presence of bias on the estimation of the consumption sometime in life of alcohol, tobacco or illegal drugs and inhalable substances, and to propose a correction for this in the case it is present. Materials and methods. Mexican National Addictions Surveys (NAS 2002, 2008, and 2011 were analyzed to compare population estimations of consumption sometime in life of tobacco, alcohol or illegal drugs and inhalable substances. A couple of alternative approaches for bias correction were developed. Results. Estimated national prevalences of consumption sometime in life of alcohol and tobacco in the NAS 2008 are not plausible. There was no evidence of bias on the consumption sometime in life of illegal drugs and inhalable substances. New estimations for tobacco and alcohol consumption sometime in life were made, which resulted in plausible values when compared to other data available. Conclusion. Future analyses regarding tobacco and alcohol using NAS 2008 data will have to rely on these newly generated data weights, that are able to reproduce the new (plausible estimations.

A sequential sampling account of response bias and speed-accuracy tradeoffs in a conflict detection task.

Science.gov (United States)

Vuckovic, Anita; Kwantes, Peter J; Humphreys, Michael; Neal, Andrew

2014-03-01

Signal Detection Theory (SDT; Green & Swets, 1966) is a popular tool for understanding decision making. However, it does not account for the time taken to make a decision, nor why response bias might change over time. Sequential sampling models provide a way of accounting for speed-accuracy trade-offs and response bias shifts. In this study, we test the validity of a sequential sampling model of conflict detection in a simulated air traffic control task by assessing whether two of its key parameters respond to experimental manipulations in a theoretically consistent way. Through experimental instructions, we manipulated participants' response bias and the relative speed or accuracy of their responses. The sequential sampling model was able to replicate the trends in the conflict responses as well as response time across all conditions. Consistent with our predictions, manipulating response bias was associated primarily with changes in the model's Criterion parameter, whereas manipulating speed-accuracy instructions was associated with changes in the Threshold parameter. The success of the model in replicating the human data suggests we can use the parameters of the model to gain an insight into the underlying response bias and speed-accuracy preferences common to dynamic decision-making tasks. © 2013 American Psychological Association

Statistical study on the self-selection bias in FDG-PET cancer screening by a questionnaire survey

International Nuclear Information System (INIS)

Kita, Tamotsu; Yano, Fuzuki; Watanabe, Sadahiro; Soga, Shigeyoshi; Hama, Yukihiro; Shinmoto, Hiroshi; Kosuda, Shigeru

2008-01-01

A questionnaire survey was performed to investigate the possible presence of self-selection bias in 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) cancer screening (PET cancer screening). Responders to the questionnaires survey consisted of 80 healthy persons, who answered whether they undergo PET cancer screening, health consciousness, age, sex, and smoking history. The univariate and multivariate analyses on the four parameters were performed between the responders who were to undergo PET cancer screening and the responders who were not. Statistically significant difference was found in health consciousness between the above-mentioned two groups by both univariate and multivariate analysis with the odds ratio of 2.088. The study indicated that self-selection bias should exist in PET cancer screening. (author)

The left inferior frontal gyrus is involved in adjusting response bias during a perceptual decision-making task.

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Reckless, Greg E; Ousdal, Olga T; Server, Andres; Walter, Henrik; Andreassen, Ole A; Jensen, Jimmy

2014-05-01

Changing the way we make decisions from one environment to another allows us to maintain optimal decision-making. One way decision-making may change is how biased one is toward one option or another. Identifying the regions of the brain that underlie the change in bias will allow for a better understanding of flexible decision-making. An event-related, perceptual decision-making task where participants had to detect a picture of an animal amongst distractors was used during functional magnetic resonance imaging. Positive and negative financial motivation were used to affect a change in response bias, and changes in decision-making behavior were quantified using signal detection theory. Response bias became relatively more liberal during both positive and negative motivated trials compared to neutral trials. For both motivational conditions, the larger the liberal shift in bias, the greater the left inferior frontal gyrus (IFG) activity. There was no relationship between individuals' belief that they used a different strategy and their actual change in response bias. The present findings suggest that the left IFG plays a role in adjusting response bias across different decision environments. This suggests a potential role for the left IFG in flexible decision-making.

Electronic surveys: how to maximise success.

Science.gov (United States)

McPeake, Joanne; Bateson, Meghan; O'Neill, Anna

2014-01-01

To draw on the researchers' experience of developing and distributing a UK-wide electronic survey. The evolution of electronic surveys in healthcare research will be discussed, as well as simple techniques that can be used to improve response rates for this type of data collection. There is an increasing use of electronic survey methods in healthcare research. However, in recent published research, electronic surveys have had lower response rates than traditional survey methods, such as postal and telephone surveys. This is a methodology paper. Electronic surveys have many advantages over traditional surveys, including a reduction in cost and ease of analysis. Drawbacks to this type of data collection include the potential for selection bias and poorer response rates. However, research teams can use a range of simple strategies to boost response rates. These approaches target the different stages of achieving a complete response: initial attraction through personalisation, engagement by having an easily accessible link to the survey, and transparency of survey length and completion though targeting the correct, and thereby interested, population. The fast, efficient and often 'free' electronic survey has many advantages over the traditional postal data collection method, including ease of analysis for what can be vast amounts of data. However, to capitalise on these benefits, researchers must carefully consider techniques to maximise response rates and minimise selection bias for their target population. Researchers can use a range of strategies to improve responses from electronic surveys, including sending up to three reminders, personalising each email, adding the updated response rate to reminder emails, and stating the average time it would take to complete the survey in the title of the email.

A Misleading Review of Response Bias: Comment on McGrath, Mitchell, Kim, and Hough (2010)

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Rohling, Martin L.; Larrabee, Glenn J.; Greiffenstein, Manfred F.; Ben-Porath, Yossef S.; Lees-Haley, Paul; Green, Paul; Greve, Kevin W.

2011-01-01

In the May 2010 issue of "Psychological Bulletin," R. E. McGrath, M. Mitchell, B. H. Kim, and L. Hough published an article entitled "Evidence for Response Bias as a Source of Error Variance in Applied Assessment" (pp. 450-470). They argued that response bias indicators used in a variety of settings typically have insufficient data to support such…

Assessing nonresponse bias at follow-up in a large prospective cohort of relatively young and mobile military service members

Directory of Open Access Journals (Sweden)

Hooper Tomoko

2010-10-01

Full Text Available Abstract Background Nonresponse bias in a longitudinal study could affect the magnitude and direction of measures of association. We identified sociodemographic, behavioral, military, and health-related predictors of response to the first follow-up questionnaire in a large military cohort and assessed the extent to which nonresponse biased measures of association. Methods Data are from the baseline and first follow-up survey of the Millennium Cohort Study. Seventy-six thousand, seven hundred and seventy-five eligible individuals completed the baseline survey and were presumed alive at the time of follow-up; of these, 54,960 (71.6% completed the first follow-up survey. Logistic regression models were used to calculate inverse probability weights using propensity scores. Results Characteristics associated with a greater probability of response included female gender, older age, higher education level, officer rank, active-duty status, and a self-reported history of military exposures. Ever smokers, those with a history of chronic alcohol consumption or a major depressive disorder, and those separated from the military at follow-up had a lower probability of response. Nonresponse to the follow-up questionnaire did not result in appreciable bias; bias was greatest in subgroups with small numbers. Conclusions These findings suggest that prospective analyses from this cohort are not substantially biased by non-response at the first follow-up assessment.

Advantages and limitations of web-based surveys: evidence from a child mental health survey.

Science.gov (United States)

Heiervang, Einar; Goodman, Robert

2011-01-01

Web-based surveys may have advantages related to the speed and cost of data collection as well as data quality. However, they may be biased by low and selective participation. We predicted that such biases would distort point-estimates such as average symptom level or prevalence but not patterns of associations with putative risk-factors. A structured psychiatric interview was administered to parents in two successive surveys of child mental health. In 2003, parents were interviewed face-to-face, whereas in 2006 they completed the interview online. In both surveys, interviews were preceded by paper questionnaires covering child and family characteristics. The rate of parents logging onto the web site was comparable to the response rate for face-to-face interviews, but the rate of full response (completing all sections of the interview) was much lower for web-based interviews. Full response was less frequent for non-traditional families, immigrant parents, and less educated parents. Participation bias affected point estimates of psychopathology but had little effect on associations with putative risk factors. The time and cost of full web-based interviews was only a quarter of that for face-to-face interviews. Web-based surveys may be performed faster and at lower cost than more traditional approaches with personal interviews. Selective participation seems a particular threat to point estimates of psychopathology, while patterns of associations are more robust.

Evidence for biasing in the CfA survey

Science.gov (United States)

Hamilton, A. J. S.

1988-01-01

Intrinsically bright galaxies appear systematically more correlated than faint galaxies in the Center for Astrophysics redshift survey. The amplification of the two-point correlation function behaves exponentially with luminosity, being essentially flat up to the knee of the luminosity function, then increasing markedly. The amplification reaches a factor of 3.5e + or - 0.4 in the very brightest galaxies. The effect is dominated by spirals rather than ellipticals, so that the correlation function of bright spirals becomes comparable to that of normal ellipticals. Similar results are obtained whether the correlation function is measured in two or three dimensions. The effect persists to separations of a correlation length or more, and is not confined to the cores of the Virgo, Coma, and Abell 1367 clusters, suggesting that the effect is caused by biasing, that is, galaxies kindle preferentially in more clustered regions, rather than by gravitational relaxation.

Practical Bias Correction in Aerial Surveys of Large Mammals: Validation of Hybrid Double-Observer with Sightability Method against Known Abundance of Feral Horse (Equus caballus) Populations.

Science.gov (United States)

Lubow, Bruce C; Ransom, Jason I

2016-01-01

Reliably estimating wildlife abundance is fundamental to effective management. Aerial surveys are one of the only spatially robust tools for estimating large mammal populations, but statistical sampling methods are required to address detection biases that affect accuracy and precision of the estimates. Although various methods for correcting aerial survey bias are employed on large mammal species around the world, these have rarely been rigorously validated. Several populations of feral horses (Equus caballus) in the western United States have been intensively studied, resulting in identification of all unique individuals. This provided a rare opportunity to test aerial survey bias correction on populations of known abundance. We hypothesized that a hybrid method combining simultaneous double-observer and sightability bias correction techniques would accurately estimate abundance. We validated this integrated technique on populations of known size and also on a pair of surveys before and after a known number was removed. Our analysis identified several covariates across the surveys that explained and corrected biases in the estimates. All six tests on known populations produced estimates with deviations from the known value ranging from -8.5% to +13.7% and corrected by our statistical models. Our results validate the hybrid method, highlight its potentially broad applicability, identify some limitations, and provide insight and guidance for improving survey designs.

Data quality assurance: an analysis of patient non-response.

Science.gov (United States)

Derby, Dustin C; Haan, Andrea; Wood, Kurt

2011-01-01

Patient satisfaction is paramount to maintaining high clinical quality assurance. This study seeks to compare response rates, response bias, and the completeness of data between paper and electronic collection modes of a chiropractic patient satisfaction survey. A convenience sample of 206 patients presenting to a chiropractic college clinic were surveyed concerning satisfaction with their chiropractic care. Paper (in-clinic and postal) and electronic modes of survey administration were compared for response rates and non-response bias. The online data collection mode resulted in fewer non-responses and a higher response rate, and did not evince response bias when compared to paper modes. The postal paper mode predicted non-response rates over the in-clinic paper and online modalities and exhibited a gender bias. This current study was a single clinic study; future studies should consider multi-clinic data collections. Busy clinic operations and available staff resources restricted the ability to conduct a random sampling of patients or to invite all eligible patients, therefore limiting the generalizability of collected survey data. Results of this study will provide data to aid development of survey protocols that efficiently, account for available human resources, and are convenient for patients while allowing for the most complete and accurate data collection possible in an educational clinic setting. Understanding patient responses across survey modes is critical for the cultivation of quality business intelligence within college teaching clinic settings. This study bridges measurement evidence from three popular data collection modalities and offers support for higher levels of quality for web-based data collection.

Evaluating telephone follow-up of a mail survey of community pharmacies.

Science.gov (United States)

Westrick, Salisa C; Mount, Jeanine K

2007-06-01

Mail and telephone are commonly used modes of survey with pharmacists. Research conducted using general population surveys consistently describes mail surveys as being less expensive but yielding lower response rates than telephone surveys. However, findings obtained from the general population may not be generalizable to pharmacist surveys. This study evaluates the effectiveness of telephone follow-up of mail survey nonrespondents by comparing the 2 survey modes on response rates, cooperation rates, cost per sample unit, and cost per usable response and evaluating potential nonresponse bias in the context of immunization activities. A census mail survey of 1,143 Washington State community pharmacies and a follow-up telephone survey of 262 randomly selected mail survey nonrespondents were compared. Both surveys included the same 15 yes/no-type questions to ask respondents about their pharmacy's involvement in immunization activities. The mail survey yielded a response rate 1 of 26.7% and a cooperation rate 1 of 26.7%, compared with 83.6% and 87.8%, respectively, for the follow-up telephone survey. With respect to cost per sample unit, the mail survey was the least expensive option ($1.20). However, when comparing cost per usable response, the mail survey was the most expensive ($4.37), and the follow-up telephone survey without an advance notification was the least expensive ($1.99). Furthermore, results suggest the presence of nonresponse bias: compared with pharmacies participating in the follow-up telephone survey, pharmacies participating in the mail survey were more likely to be involved in in-house immunization services but less likely to be involved in outsourced services. The telephone survey achieved higher outcome rates with reduced cost per usable response. A telephone survey is a viable mode that holds promise in pharmacy practice research. Maximizing response rates and assessing potential nonresponse bias should be a standard practice among pharmacy

Racial, gender, and socioeconomic status bias in senior medical student clinical decision-making: a national survey.

Science.gov (United States)

Williams, Robert L; Romney, Crystal; Kano, Miria; Wright, Randy; Skipper, Betty; Getrich, Christina M; Sussman, Andrew L; Zyzanski, Stephen J

2015-06-01

Research suggests stereotyping by clinicians as one contributor to racial and gender-based health disparities. It is necessary to understand the origins of such biases before interventions can be developed to eliminate them. As a first step toward this understanding, we tested for the presence of bias in senior medical students. The purpose of the study was to determine whether bias based on race, gender, or socioeconomic status influenced clinical decision-making among medical students. We surveyed seniors at 84 medical schools, who were required to choose between two clinically equivalent management options for a set of cardiac patient vignettes. We examined variations in student recommendations based on patient race, gender, and socioeconomic status. The study included senior medical students. We investigated the percentage of students selecting cardiac procedural options for vignette patients, analyzed by patient race, gender, and socioeconomic status. Among 4,603 returned surveys, we found no evidence in the overall sample supporting racial or gender bias in student clinical decision-making. Students were slightly more likely to recommend cardiac procedural options for black (43.9 %) vs. white (42 %, p = .03) patients; there was no difference by patient gender. Patient socioeconomic status was the strongest predictor of student recommendations, with patients described as having the highest socioeconomic status most likely to receive procedural care recommendations (50.3 % vs. 43.2 % for those in the lowest socioeconomic status group, p socioeconomic status, geographic variations, and the influence of interactions between patient race and gender on student recommendations.

Post-precipitation bias in band-tailed pigeon surveys conducted at mineral sites

Science.gov (United States)

Overton, C.T.; Schmitz, R.A.; Casazza, Michael L.

2005-01-01

Many animal surveys to estimate populations or index trends include protocol prohibiting counts during rain but fail to address effects of rainfall preceding the count. Prior research on Pacific Coast band-tailed pigeons (Patagioenas fasciata monilis) documented declines in use of mineral sites during rainfall. We hypothesized that prior precipitation was associated with a short-term increase in use of mineral sites following rain. We conducted weekly counts of band-tailed pigeons at 19 Pacific Northwest mineral sites in 2001 and 20 sites in 2002. Results from regression analysis indicated higher counts ???2 days after rain (11.31??5.00% [x????SE]) compared to ???3 days. Individual index counts conducted ???2 days after rain were biased high, resulting in reduced ability to accurately estimate population trends. Models of band-tailed pigeon visitation rates throughout the summer showed increased mineral-site counts during both June and August migration periods, relative to the July breeding period. Our research supported previous studies recommending that mineral-site counts used to index the band-tailed pigeon population be conducted during July. We further recommend conducting counts >3 days after rain to avoid weather-related bias in index estimation. The design of other population sampling strategies that rely on annual counts should consider the influence of aberrant weather not only coincident with but also preceding surveys if weather patterns are thought to influence behavior or detection probability of target species.

Effects of temporally biased watering on the nitrogen response of Chenopodium album

Science.gov (United States)

Kinugasa, Toshihiko; Hozumi, Yumi

2017-07-01

Plant growth responses to an increasing N deposition are stimulated by an increase in annual precipitation, but such a stimulation has not always been found. We hypothesized that the effect of precipitation on plant N responses can change with temporally biased precipitation: a plant N response will be suppressed when precipitation is lower in the late growing period because larger plants are more susceptible to water limitations. We grew Chenopodium album under a high and low N application level with three watering patterns while maintaining the total supplied watering amount during the experimental period: constant watering, low watering in the first period and high watering in the latter period, and high watering in the first period and low watering in the latter period. The watering pattern did not affect plant dry mass under low N conditions. The plant dry mass under high N conditions was reduced by low watering in the first period, but the reduction was fully compensated in the subsequent high watering period by the stimulation of photosynthesis. Low watering following high watering under high N conditions did not suppress plant growth, but partial leaf wilting was observed at the end of the experimental period. Finally, at the end of the experiment, the response of plant dry mass to N was not different among the watering patterns. We concluded that a plant's response to increasing N deposition could be affected by temporally biased precipitation, depending on the scale of the precipitation bias and the ability of the plant to compensate or mitigate growth inhibition due to a water deficit. Precipitation deficits later in the growing period may be more detrimental to plant growth and can reduce plant responses to an increasing N deposition.

Effect of vicarious fear learning on children's heart rate responses and attentional bias for novel animals.

Science.gov (United States)

Reynolds, Gemma; Field, Andy P; Askew, Chris

2014-10-01

Research with children has shown that vicarious learning can result in changes to 2 of Lang's (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang's final response system) and attentional bias. The study used Askew and Field's (2007) vicarious learning procedure and demonstrated fear-related increases in children's cognitive, behavioral, and physiological responses. Cognitive and behavioral changes were retested 1 week and 1 month later, and remained elevated. In addition, a visual search task demonstrated that fear-related vicarious learning creates an attentional bias for novel animals, which is moderated by increases in fear beliefs during learning. The findings demonstrate that vicarious learning leads to lasting changes in all 3 of Lang's anxiety response systems and is sufficient to create attentional bias to threat in children. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Velocity Segregation and Systematic Biases In Velocity Dispersion Estimates with the SPT-GMOS Spectroscopic Survey

Science.gov (United States)

Bayliss, Matthew. B.; Zengo, Kyle; Ruel, Jonathan; Benson, Bradford A.; Bleem, Lindsey E.; Bocquet, Sebastian; Bulbul, Esra; Brodwin, Mark; Capasso, Raffaella; Chiu, I.-non; McDonald, Michael; Rapetti, David; Saro, Alex; Stalder, Brian; Stark, Antony A.; Strazzullo, Veronica; Stubbs, Christopher W.; Zenteno, Alfredo

2017-03-01

The velocity distribution of galaxies in clusters is not universal; rather, galaxies are segregated according to their spectral type and relative luminosity. We examine the velocity distributions of different populations of galaxies within 89 Sunyaev Zel’dovich (SZ) selected galaxy clusters spanning 0.28GMOS spectroscopic survey, supplemented by additional published spectroscopy, resulting in a final spectroscopic sample of 4148 galaxy spectra—2868 cluster members. The velocity dispersion of star-forming cluster galaxies is 17 ± 4% greater than that of passive cluster galaxies, and the velocity dispersion of bright (m< {m}* -0.5) cluster galaxies is 11 ± 4% lower than the velocity dispersion of our total member population. We find good agreement with simulations regarding the shape of the relationship between the measured velocity dispersion and the fraction of passive versus star-forming galaxies used to measure it, but we find a small offset between this relationship as measured in data and simulations, which suggests that our dispersions are systematically low by as much as 3% relative to simulations. We argue that this offset could be interpreted as a measurement of the effective velocity bias that describes the ratio of our observed velocity dispersions and the intrinsic velocity dispersion of dark matter particles in a published simulation result. Measuring velocity bias in this way suggests that large spectroscopic surveys can improve dispersion-based mass-observable scaling relations for cosmology even in the face of velocity biases, by quantifying and ultimately calibrating them out.

OBJECTS IN KEPLER'S MIRROR MAY BE LARGER THAN THEY APPEAR: BIAS AND SELECTION EFFECTS IN TRANSITING PLANET SURVEYS

International Nuclear Information System (INIS)

Gaidos, Eric; Mann, Andrew W.

2013-01-01

Statistical analyses of large surveys for transiting planets such as the Kepler mission must account for systematic errors and biases. Transit detection depends not only on the planet's radius and orbital period, but also on host star properties. Thus, a sample of stars with transiting planets may not accurately represent the target population. Moreover, targets are selected using criteria such as a limiting apparent magnitude. These selection effects, combined with uncertainties in stellar radius, lead to biases in the properties of transiting planets and their host stars. We quantify possible biases in the Kepler survey. First, Eddington bias produced by a steep planet radius distribution and uncertainties in stellar radius results in a 15%-20% overestimate of planet occurrence. Second, the magnitude limit of the Kepler target catalog induces Malmquist bias toward large, more luminous stars and underestimation of the radii of about one-third of candidate planets, especially those larger than Neptune. Third, because metal-poor stars are smaller, stars with detected planets will be very slightly (<0.02 dex) more metal-poor than the target average. Fourth, uncertainties in stellar radii produce correlated errors in planet radius and stellar irradiation. A previous finding, that highly irradiated giants are more likely to have 'inflated' radii, remains significant, even accounting for this effect. In contrast, transit depth is negatively correlated with stellar metallicity even in the absence of any intrinsic correlation, and a previous claim of a negative correlation between giant planet transit depth and stellar metallicity is probably an artifact.

Improving Survey Response Rates in Online Panels

DEFF Research Database (Denmark)

Pedersen, Mogens Jin; Nielsen, Christian Videbæk

2016-01-01

Identifying ways to efficiently maximize the response rate to surveys is important to survey-based research. However, evidence on the response rate effect of donation incentives and especially altruistic and egotistic-type text appeal interventions is sparse and ambiguous. By a randomized survey...... experiment among 6,162 members of an online survey panel, this article shows how low-cost incentives and cost-free text appeal interventions may impact the survey response rate in online panels. The experimental treatments comprise (a) a cash prize lottery incentive, (b) two donation incentives equating...... survey response with a monetary donation to a good cause, (c) an egotistic-type text appeal, and (d) an altruistic-type text appeal. Relative to a control group, we find higher response rates among the recipients of the egotistic-type text appeal and the lottery incentive. Donation incentives yield lower...

Effect of Vicarious Fear Learning on Children’s Heart Rate Responses and Attentional Bias for Novel Animals

Science.gov (United States)

2014-01-01

Research with children has shown that vicarious learning can result in changes to 2 of Lang’s (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang’s final response system) and attentional bias. The study used Askew and Field’s (2007) vicarious learning procedure and demonstrated fear-related increases in children’s cognitive, behavioral, and physiological responses. Cognitive and behavioral changes were retested 1 week and 1 month later, and remained elevated. In addition, a visual search task demonstrated that fear-related vicarious learning creates an attentional bias for novel animals, which is moderated by increases in fear beliefs during learning. The findings demonstrate that vicarious learning leads to lasting changes in all 3 of Lang’s anxiety response systems and is sufficient to create attentional bias to threat in children. PMID:25151521

Motivation alters response bias and neural activation patterns in a perceptual decision-making task.

Science.gov (United States)

Reckless, G E; Bolstad, I; Nakstad, P H; Andreassen, O A; Jensen, J

2013-05-15

Motivation has been demonstrated to affect individuals' response strategies in economic decision-making, however, little is known about how motivation influences perceptual decision-making behavior or its related neural activity. Given the important role motivation plays in shaping our behavior, a better understanding of this relationship is needed. A block-design, continuous performance, perceptual decision-making task where participants were asked to detect a picture of an animal among distractors was used during functional magnetic resonance imaging (fMRI). The effect of positive and negative motivation on sustained activity within regions of the brain thought to underlie decision-making was examined by altering the monetary contingency associated with the task. In addition, signal detection theory was used to investigate the effect of motivation on detection sensitivity, response bias and response time. While both positive and negative motivation resulted in increased sustained activation in the ventral striatum, fusiform gyrus, left dorsolateral prefrontal cortex (DLPFC) and ventromedial prefrontal cortex, only negative motivation resulted in the adoption of a more liberal, closer to optimal response bias. This shift toward a liberal response bias correlated with increased activation in the left DLPFC, but did not result in improved task performance. The present findings suggest that motivation alters aspects of the way perceptual decisions are made. Further, this altered response behavior is reflected in a change in left DLPFC activation, a region involved in the computation of perceptual decisions. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Anxiety-related biases in visual orienting and spatial motor response selection independently assessed by a probe-classification task

NARCIS (Netherlands)

Schrooten, M.G.S.; Smulders, F.T.Y.; Mogg, K.; Bradley, B.P.

2012-01-01

This dot-probe study assessed anxiety-related biases in visual attentional orienting and spatial motor response selection (motor attention) in high- and low-trait-anxious adults, and whether anxiety-related biases depend on response speed. Emotional-neutral word pairs appeared for 14 or 500 ms, with

Utilizing the Total Design Method in medicine: maximizing response rates in long, non-incentivized, personal questionnaire postal surveys.

Science.gov (United States)

Kazzazi, Fawz; Haggie, Rebecca; Forouhi, Parto; Kazzazi, Nazar; Malata, Charles M

2018-01-01

Maximizing response rates in questionnaires can improve their validity and quality by reducing non-response bias. A comprehensive analysis is essential for producing reasonable conclusions in patient-reported outcome research particularly for topics of a sensitive nature. This often makes long (≥7 pages) questionnaires necessary but these have been shown to reduce response rates in mail surveys. Our work adapted the "Total Design Method," initially produced for commercial markets, to raise response rates in a long (total: 11 pages, 116 questions), non-incentivized, very personal postal survey sent to almost 350 women. A total of 346 women who had undergone mastectomy and immediate breast reconstruction from 2008-2014 (inclusive) at Addenbrooke's University Hospital were sent our study pack (Breast-Q satisfaction questionnaire and support documents) using our modified "Total Design Method." Participants were sent packs and reminders according to our designed schedule. Of the 346 participants, we received 258 responses, an overall response rate of 74.5% with a useable response rate of 72.3%. One hundred and six responses were received before the week 1 reminder (30.6%), 120 before week 3 (34.6%), 225 before the week 7 reminder (64.6%) and the remainder within 3 weeks of the final pack being sent. The median age of patients that the survey was sent to, and the median age of the respondents, was 54 years. In this study, we have demonstrated the successful implementation of a novel approach to postal surveys. Despite the length of the questionnaire (nine pages, 116 questions) and limitations of expenses to mail a survey to ~350 women, we were able to attain a response rate of 74.6%.

Measurement and control of bias in patient reported outcomes using multidimensional item response theory.

Science.gov (United States)

Dowling, N Maritza; Bolt, Daniel M; Deng, Sien; Li, Chenxi

2016-05-26

Patient-reported outcome (PRO) measures play a key role in the advancement of patient-centered care research. The accuracy of inferences, relevance of predictions, and the true nature of the associations made with PRO data depend on the validity of these measures. Errors inherent to self-report measures can seriously bias the estimation of constructs assessed by the scale. A well-documented disadvantage of self-report measures is their sensitivity to response style (RS) effects such as the respondent's tendency to select the extremes of a rating scale. Although the biasing effect of extreme responding on constructs measured by self-reported tools has been widely acknowledged and studied across disciplines, little attention has been given to the development and systematic application of methodologies to assess and control for this effect in PRO measures. We review the methodological approaches that have been proposed to study extreme RS effects (ERS). We applied a multidimensional item response theory model to simultaneously estimate and correct for the impact of ERS on trait estimation in a PRO instrument. Model estimates were used to study the biasing effects of ERS on sum scores for individuals with the same amount of the targeted trait but different levels of ERS. We evaluated the effect of joint estimation of multiple scales and ERS on trait estimates and demonstrated the biasing effects of ERS on these trait estimates when used as explanatory variables. A four-dimensional model accounting for ERS bias provided a better fit to the response data. Increasing levels of ERS showed bias in total scores as a function of trait estimates. The effect of ERS was greater when the pattern of extreme responding was the same across multiple scales modeled jointly. The estimated item category intercepts provided evidence of content independent category selection. Uncorrected trait estimates used as explanatory variables in prediction models showed downward bias. A

Participation and factors associated with late or non-response to an online survey in primary care.

Science.gov (United States)

Aerny-Perreten, Nicole; Domínguez-Berjón, Ma Felicitas; Esteban-Vasallo, María D; García-Riolobos, Carmen

2015-08-01

Online surveys have several advantages, but a low response rate is common and it is uncertain how results are affected. Response inducement techniques can be used to overcome this problem. The objectives of this study were to describe the percentage of change in the response rate after reminders and to analyse the characteristics associated with non-response and late response based on the survey results, as well as by applying archival and extrapolation techniques. In the Autonomous Community of Madrid, an online questionnaire about cancer prevention was sent to a random sample of primary care health professionals (3586 physicians and nurses). Two reminders were sent later. The percentage of change in response rates after reminders, global and by demographic and health care characteristics of participants; and factors associated with non-response and late response were analysed using response rates and odds ratios (ORs). After the reminders, the response rate increased from 22.6% to 32.9% and to 39.4%. Non-response was associated with age [OR: 3.14; confidence interval (CI) 95%: 2.23-4.42 for aged >60 years], gender and functional area. Further, a higher response rate after reminders was observed in professionals with heavier workloads (OR: 1.46; CI 95%: 1.08-1.97) and in those who stated a lower relevance of cancer prevention in primary care. After electronic reminders, the response rate increased, especially among professionals with the highest workloads and a minor interest in the survey topic. However, possible bias associated with non-response remains and the factors behind this should be examined in future research. © 2015 John Wiley & Sons, Ltd.

Predicting survey responses: how and why semantics shape survey statistics on organizational behaviour.

Directory of Open Access Journals (Sweden)

Jan Ketil Arnulf

Full Text Available Some disciplines in the social sciences rely heavily on collecting survey responses to detect empirical relationships among variables. We explored whether these relationships were a priori predictable from the semantic properties of the survey items, using language processing algorithms which are now available as new research methods. Language processing algorithms were used to calculate the semantic similarity among all items in state-of-the-art surveys from Organisational Behaviour research. These surveys covered areas such as transformational leadership, work motivation and work outcomes. This information was used to explain and predict the response patterns from real subjects. Semantic algorithms explained 60-86% of the variance in the response patterns and allowed remarkably precise prediction of survey responses from humans, except in a personality test. Even the relationships between independent and their purported dependent variables were accurately predicted. This raises concern about the empirical nature of data collected through some surveys if results are already given a priori through the way subjects are being asked. Survey response patterns seem heavily determined by semantics. Language algorithms may suggest these prior to administering a survey. This study suggests that semantic algorithms are becoming new tools for the social sciences, opening perspectives on survey responses that prevalent psychometric theory cannot explain.

The Accumulative Effect of Concentric‐Biased and Eccentric‐ Biased Exercise on Cardiorespiratory and Metabolic Responses to Subsequent Low‐Intensity Exercise: A Preliminary Study

Directory of Open Access Journals (Sweden)

Gavin James Peter

2015-12-01

Full Text Available The study investigated the accumulative effect of concentric-biased and eccentric-biased exercise on cardiorespiratory, metabolic and neuromuscular responses to low-intensity exercise performed hours later. Fourteen young men cycled at low-intensity (~60 rpm at 50% maximal oxygen uptake for 10 min before, and 12 h after: concentric-biased, single-leg cycling exercise (CON (performed ~19:30 h and eccentric-biased, double-leg knee extension exercise (ECC (~06:30 h the following morning. Respiratory measures were sampled breath-by-breath, with oxidation values derived from stoichiometry equations. Knee extensor neuromuscular function was assessed before and after CON and ECC. Cardiorespiratory responses during low-intensity cycling were unchanged by accumulative CON and ECC. The RER was lower during low-intensity exercise 12 h after CON and ECC (0.88 ± 0.08, when compared to baseline (0.92 ± 0.09; p = 0.02. Fat oxidation increased from baseline (0.24 ± 0.2 g·min1 to 12 h after CON and ECC (0.39 ± 0.2 g·min1; p = 0.01. Carbohydrate oxidation decreased from baseline (1.59 ± 0.4 g·min-1 to 12 h after CON and ECC (1.36 ± 0.4 g·min1; p = 0.03. These were accompanied by knee extensor force loss (right leg: -11.6%, p < 0.001; left leg: -10.6%, p = 0.02 and muscle soreness (right leg: 2.5 ± 0.9, p < 0.0001; left leg: 2.3 ± 1.2, p < 0.01. Subsequent concentric-biased and eccentric-biased exercise led to increased fat oxidation and decreased carbohydrate oxidation, without impairing cardiorespiration, during low-intensity cycling. An accumulation of fatiguing and damaging exercise increases fat utilisation during low intensity exercise performed as little as 12 h later.

Triangles in ROC space: History and theory of "nonparametric" measures of sensitivity and response bias.

Science.gov (United States)

Macmillan, N A; Creelman, C D

1996-06-01

Can accuracy and response bias in two-stimulus, two-response recognition or detection experiments be measured nonparametrically? Pollack and Norman (1964) answered this question affirmatively for sensitivity, Hodos (1970) for bias: Both proposed measures based on triangular areas in receiver-operating characteristic space. Their papers, and especially a paper by Grier (1971) that provided computing formulas for the measures, continue to be heavily cited in a wide range of content areas. In our sample of articles, most authors described triangle-based measures as making fewer assumptions than measures associated with detection theory. However, we show that statistics based on products or ratios of right triangle areas, including a recently proposed bias index and a not-yetproposed but apparently plausible sensitivity index, are consistent with a decision process based on logistic distributions. Even the Pollack and Norman measure, which is based on non-right triangles, is approximately logistic for low values of sensitivity. Simple geometric models for sensitivity and bias are not nonparametric, even if their implications are not acknowledged in the defining publications.

Extent, Awareness and Perception of Dissemination Bias in Qualitative Research: An Explorative Survey

Science.gov (United States)

Toews, Ingrid; Glenton, Claire; Lewin, Simon; Berg, Rigmor C.; Noyes, Jane; Booth, Andrew; Marusic, Ana; Malicki, Mario; Munthe-Kaas, Heather M.; Meerpohl, Joerg J.

2016-01-01

Background Qualitative research findings are increasingly used to inform decision-making. Research has indicated that not all quantitative research on the effects of interventions is disseminated or published. The extent to which qualitative researchers also systematically underreport or fail to publish certain types of research findings, and the impact this may have, has received little attention. Methods A survey was delivered online to gather data regarding non-dissemination and dissemination bias in qualitative research. We invited relevant stakeholders through our professional networks, authors of qualitative research identified through a systematic literature search, and further via snowball sampling. Results 1032 people took part in the survey of whom 859 participants identified as researchers, 133 as editors and 682 as peer reviewers. 68.1% of the researchers said that they had conducted at least one qualitative study that they had not published in a peer-reviewed journal. The main reasons for non-dissemination were that a publication was still intended (35.7%), resource constraints (35.4%), and that the authors gave up after the paper was rejected by one or more journals (32.5%). A majority of the editors and peer reviewers “(strongly) agreed” that the main reasons for rejecting a manuscript of a qualitative study were inadequate study quality (59.5%; 68.5%) and inadequate reporting quality (59.1%; 57.5%). Of 800 respondents, 83.1% “(strongly) agreed” that non-dissemination and possible resulting dissemination bias might undermine the willingness of funders to support qualitative research. 72.6% and 71.2%, respectively, “(strongly) agreed” that non-dissemination might lead to inappropriate health policy and health care. Conclusions The proportion of non-dissemination in qualitative research is substantial. Researchers, editors and peer reviewers play an important role in this. Non-dissemination and resulting dissemination bias may impact on

Extent, Awareness and Perception of Dissemination Bias in Qualitative Research: An Explorative Survey.

Science.gov (United States)

Toews, Ingrid; Glenton, Claire; Lewin, Simon; Berg, Rigmor C; Noyes, Jane; Booth, Andrew; Marusic, Ana; Malicki, Mario; Munthe-Kaas, Heather M; Meerpohl, Joerg J

2016-01-01

Qualitative research findings are increasingly used to inform decision-making. Research has indicated that not all quantitative research on the effects of interventions is disseminated or published. The extent to which qualitative researchers also systematically underreport or fail to publish certain types of research findings, and the impact this may have, has received little attention. A survey was delivered online to gather data regarding non-dissemination and dissemination bias in qualitative research. We invited relevant stakeholders through our professional networks, authors of qualitative research identified through a systematic literature search, and further via snowball sampling. 1032 people took part in the survey of whom 859 participants identified as researchers, 133 as editors and 682 as peer reviewers. 68.1% of the researchers said that they had conducted at least one qualitative study that they had not published in a peer-reviewed journal. The main reasons for non-dissemination were that a publication was still intended (35.7%), resource constraints (35.4%), and that the authors gave up after the paper was rejected by one or more journals (32.5%). A majority of the editors and peer reviewers "(strongly) agreed" that the main reasons for rejecting a manuscript of a qualitative study were inadequate study quality (59.5%; 68.5%) and inadequate reporting quality (59.1%; 57.5%). Of 800 respondents, 83.1% "(strongly) agreed" that non-dissemination and possible resulting dissemination bias might undermine the willingness of funders to support qualitative research. 72.6% and 71.2%, respectively, "(strongly) agreed" that non-dissemination might lead to inappropriate health policy and health care. The proportion of non-dissemination in qualitative research is substantial. Researchers, editors and peer reviewers play an important role in this. Non-dissemination and resulting dissemination bias may impact on health care research, practice and policy. More

Extent, Awareness and Perception of Dissemination Bias in Qualitative Research: An Explorative Survey.

Directory of Open Access Journals (Sweden)

Ingrid Toews

Full Text Available Qualitative research findings are increasingly used to inform decision-making. Research has indicated that not all quantitative research on the effects of interventions is disseminated or published. The extent to which qualitative researchers also systematically underreport or fail to publish certain types of research findings, and the impact this may have, has received little attention.A survey was delivered online to gather data regarding non-dissemination and dissemination bias in qualitative research. We invited relevant stakeholders through our professional networks, authors of qualitative research identified through a systematic literature search, and further via snowball sampling.1032 people took part in the survey of whom 859 participants identified as researchers, 133 as editors and 682 as peer reviewers. 68.1% of the researchers said that they had conducted at least one qualitative study that they had not published in a peer-reviewed journal. The main reasons for non-dissemination were that a publication was still intended (35.7%, resource constraints (35.4%, and that the authors gave up after the paper was rejected by one or more journals (32.5%. A majority of the editors and peer reviewers "(strongly agreed" that the main reasons for rejecting a manuscript of a qualitative study were inadequate study quality (59.5%; 68.5% and inadequate reporting quality (59.1%; 57.5%. Of 800 respondents, 83.1% "(strongly agreed" that non-dissemination and possible resulting dissemination bias might undermine the willingness of funders to support qualitative research. 72.6% and 71.2%, respectively, "(strongly agreed" that non-dissemination might lead to inappropriate health policy and health care.The proportion of non-dissemination in qualitative research is substantial. Researchers, editors and peer reviewers play an important role in this. Non-dissemination and resulting dissemination bias may impact on health care research, practice and policy

Systematic Biases in Weak Lensing Cosmology with the Dark Energy Survey

Energy Technology Data Exchange (ETDEWEB)

Samuroff, Simon [Manchester U.

2017-01-01

This thesis sets out a practical guide to applying shear measurements as a cosmological tool. We first present one of two science-ready galaxy shape catalogues from Year 1 of the Dark Energy Survey (DES Y1), which covers 1500 square degrees in four bands $griz$, with a median redshift of $0.59$. We describe the shape measurement process implemented by the DES Y1 imshape catalogue, which contains 21.9 million high-quality $r$-band bulge/disc fits. In Chapter 3 a new suite of image simulations, referred to as Hoopoe, are presented. The Hoopoe dataset is tailored to DES Y1 and includes realistic blending, spatial masks and variation in the point spread function. We derive shear corrections, which we show are robust to changes in calibration method, galaxy binning and variance within the simulated dataset. Sources of systematic uncertainty in the simulation-based shear calibration are discussed, leading to a final estimate of the $1\\sigma$ uncertainties in the residual multiplica tive bias after calibration of 0.025. Chapter 4 describes an extension of the analysis on the Hoopoe simulations into a detailed investigation of the impact of galaxy neighbours on shape measurement and shear cosmology. Four mechanisms by which neighbours can have a non-negligible influence on shear measurement are identified. These effects, if ignored, would contribute a net multiplicative bias of $m \\sim 0.03 - 0.09$ in DES Y1, though the precise impact will depend on both the measurement code and the selection cuts applied. We use the cosmological inference pipeline of DES Y1 to explore the cosmological implications of neighbour bias and show that omitting blending from the calibration simulation for DES Y1 would bias the inferred clustering amplitude $S_8 \\equiv \\sigma_8 (\\omegam /0.3)^{0.5}$ by $1.5 \\sigma$ towards low values. Finally, we use the Hoopoe simulations to test the effect of neighbour-induced spatial correlations in the multiplicative bias. We find the cosmo logical

BIAS IN THE MEASUREMENT OF QUALITY OF LIFE: RESPONSE SHIFT

Directory of Open Access Journals (Sweden)

Yesim SENOL

2006-10-01

Full Text Available Quality of Life (QoL is a descriptive term that refers to people’s emotional, social and physical wellbeing, and their ability to function in the ordinary task of living. The importance of QoL makes it critical to improve and refine measure to understand patients’ experience of health, illness and treatment. However individuals change with time and the basis on which they make a QoL judgment may also change, a phenomenon increasingly referred to as response shift. The definition of response shift is recalibration of internal standards of measurement and reconceptualization of the meaning of item. The purpose of study is to discuss the effects of response shift bias. [TAF Prev Med Bull 2006; 5(5.000: 382-389

Attrition Bias in Panel Data: A Sheep in Wolf's Clothing? A Case Study Based on the Mabel Survey.

Science.gov (United States)

Cheng, Terence C; Trivedi, Pravin K

2015-09-01

This paper investigates the nature and consequences of sample attrition in a unique longitudinal survey of medical doctors. We describe the patterns of non-response and examine if attrition affects the econometric analysis of medical labour market outcomes using the estimation of physician earnings equations as a case study. We compare the econometric gestimates obtained from a number of different modelling strategies, which are as follows: balanced versus unbalanced samples; an attrition model for panel data based on the classic sample selection model; and a recently developed copula-based selection model. Descriptive evidence shows that doctors who work longer hours, have lower years of experience, are overseas trained and have changed their work location are more likely to drop out. Our analysis suggests that the impact of attrition on inference about the earnings of general practitioners is small. For specialists, there appears to be some evidence for an economically significant bias. Finally, we discuss how the top-up samples in the Medicine in Australia: Balancing Employment and Life survey can be used to address the problem of panel attrition. Copyright © 2015 John Wiley & Sons, Ltd.

Self-reporting bias in Chinook salmon sport fisheries in Idaho: implications for roving creel surveys

Science.gov (United States)

McCormick, Joshua L.; Quist, Michael C.; Schill, Daniel J.

2013-01-01

Self-reporting bias in sport fisheries of Chinook Salmon Oncorhynchus tshawytscha in Idaho was quantified by comparing observed and angler-reported data. A total of 164 observed anglers fished for 541 h and caught 74 Chinook Salmon. Fifty-eight fish were harvested and 16 were released. Anglers reported fishing for 604 h, an overestimate of 63 h. Anglers reported catching 66 fish; four less harvested and four less released fish were reported than observed. A Monte Carlo simulation revealed that when angler-reported data were used, total catch was underestimated by 14–15 fish (19–20%) using the ratio-of-means estimator to calculate mean catch rate. Negative bias was reduced to six fish (8%) when the means-of-ratio estimator was used. Multiple linear regression models to predict reporting bias in time fished had poor predictive value. However, actual time fished and a categorical covariate indicating whether the angler fished continuously during their fishing trip were two variables that were present in all of the top a priori models evaluated. Underreporting of catch and overreporting of time fished by anglers present challenges when managing Chinook Salmon sport fisheries. However, confidence intervals were near target levels and using more liberal definitions of angling when estimating effort in creel surveys may decrease sensitivity to bias in angler-reported data.

A Comparison of Response Rate, Response Time, and Costs of Mail and Electronic Surveys.

Science.gov (United States)

Shannon, David M.; Bradshaw, Carol C.

2002-01-01

Compared response rates, response time, and costs of mail and electronic surveys using a sample of 377 college faculty members. Mail surveys yielded a higher response rate and a lower rate of undeliverable surveys, but response time was longer and costs were higher than for electronic surveys. (SLD)

Beyond attentional bias: a perceptual bias in a dot-probe task.

Science.gov (United States)

Bocanegra, Bruno R; Huijding, Jorg; Zeelenberg, René

2012-12-01

Previous dot-probe studies indicate that threat-related face cues induce a bias in spatial attention. Independently of spatial attention, a recent psychophysical study suggests that a bilateral fearful face cue improves low spatial-frequency perception (LSF) and impairs high spatial-frequency perception (HSF). Here, we combine these separate lines of research within a single dot-probe paradigm. We found that a bilateral fearful face cue, compared with a bilateral neutral face cue, speeded up responses to LSF targets and slowed down responses to HSF targets. This finding is important, as it shows that emotional cues in dot-probe tasks not only bias where information is preferentially processed (i.e., an attentional bias in spatial location), but also bias what type of information is preferentially processed (i.e., a perceptual bias in spatial frequency). PsycINFO Database Record (c) 2012 APA, all rights reserved.

Gender-biased behavior at work: what can surveys tell us about the link between sexual harassment and gender discrimination?

OpenAIRE

Antecol, Heather; Barcus, Vanessa E.; Cobb-Clark, Deborah A.

2007-01-01

This paper examines the links between survey-based reports of sexual harassment and gender discrimination. In particular, we are interested in assessing whether these concepts measure similar forms of gender-biased behavior and whether they have the same effect on workers' job satisfaction and intentions to leave their jobs. Our results provide little support for the notion that survey-based measures of sexual harassment and gender discrimination capture the same underlying behavior. Responde...

Maximising nurses' and midwives' response rates to surveys.

Science.gov (United States)

Cooper, Alannah Louise; Brown, Janie

2017-12-18

Low response rates to surveys have been a long-standing issue in research. This includes research involving nurses and midwives. To gain representative samples, appropriate measures to maximise response rates need to be used. To explore ways to maximise response rates from nurses and midwives, using a hospital-wide survey as an example. All nurses and midwives at the study hospital were invited to participate in a survey. To encourage participation and elicit an adequate response rate, several strategies were used. A total of 1,000 surveys were distributed and 319 (32%) were returned. All the required age groups, levels of experience and types of nursing registration were represented in the responses and data saturation was achieved. It is important to pay attention to obtaining a representative sample. Further investigation of response rates to surveys by nurses and midwives is warranted. Strategies to maximise response rates from a target population should be used when conducting surveys. ©2017 RCN Publishing Company Ltd. All rights reserved. Not to be copied, transmitted or recorded in any way, in whole or part, without prior permission of the publishers.

Effect of survey mode on response patterns

DEFF Research Database (Denmark)

Christensen, Anne Illemann; Ekholm, Ola; Glümer, Charlotte

2014-01-01

.7%). Marital status, ethnic background and highest completed education were associated with non-response in both modes. Furthermore, sex and age were associated with non-response in the self-administered mode. No significant mode effects were observed for indicators related to use of health services......BACKGROUND: While face-to-face interviews are considered the gold standard of survey modes, self-administered questionnaires are often preferred for cost and convenience. This article examines response patterns in two general population health surveys carried out by face-to-face interview and self......-administered questionnaire, respectively. METHOD: Data derives from a health interview survey in the Region of Southern Denmark (face-to-face interview) and The Danish Health and Morbidity Survey 2010 (self-administered questionnaire). Identical questions were used in both surveys. Data on all individuals were obtained from...

PLUTINO DETECTION BIASES, INCLUDING THE KOZAI RESONANCE

International Nuclear Information System (INIS)

Lawler, S. M.; Gladman, B.

2013-01-01

Because of their relative proximity within the trans-Neptunian region, the plutinos (objects in the 3:2 mean-motion resonance with Neptune) are numerous in flux-limited catalogs, and well-studied theoretically. We perform detailed modeling of the on-sky detection biases for plutinos, with special attention to those that are simultaneously in the Kozai resonance. In addition to the normal 3:2 resonant argument libration, Kozai plutinos also show periodic oscillations in eccentricity and inclination, coupled to the argument of perihelion (ω) oscillation. Due to the mean-motion resonance, plutinos avoid coming to pericenter near Neptune's current position in the ecliptic plane. Because Kozai plutinos are restricted to certain values of ω, perihelion always occurs out of the ecliptic plane, biasing ecliptic surveys against finding these objects. The observed Kozai plutino fraction f koz obs has been measured by several surveys, finding values between 8% and 25%, while the true Kozai plutino fraction f koz true has been predicted to be between 10% and 30% by different giant planet migration simulations. We show that f koz obs varies widely depending on the ecliptic latitude and longitude of the survey, so debiasing to find the true ratio is complex. Even a survey that covers most or all of the sky will detect an apparent Kozai fraction that is different from f koz true . We present a map of the on-sky plutino Kozai fraction that would be detected by all-sky flux-limited surveys. This will be especially important for the Panoramic Survey Telescope and Rapid Response System and Large Synoptic Survey Telescope projects, which may detect large numbers of plutinos as they sweep the sky. f koz true and the distribution of the orbital elements of Kozai plutinos may be a diagnostic of giant planet migration; future migration simulations should provide details on their resonant Kozai populations.

Nonresponse bias in randomized controlled experiments in criminology: Putting the Queensland Community Engagement Trial (QCET) under a microscope.

Science.gov (United States)

Antrobus, Emma; Elffers, Henk; White, Gentry; Mazerolle, Lorraine

2013-01-01

The goal of this article is to examine whether or not the results of the Queensland Community Engagement Trial (QCET)-a randomized controlled trial that tested the impact of procedural justice policing on citizen attitudes toward police-were affected by different types of nonresponse bias. We use two methods (Cochrane and Elffers methods) to explore nonresponse bias: First, we assess the impact of the low response rate by examining the effects of nonresponse group differences between the experimental and control conditions and pooled variance under different scenarios. Second, we assess the degree to which item response rates are influenced by the control and experimental conditions. Our analysis of the QCET data suggests that our substantive findings are not influenced by the low response rate in the trial. The results are robust even under extreme conditions, and statistical significance of the results would only be compromised in cases where the pooled variance was much larger for the nonresponse group and the difference between experimental and control conditions was greatly diminished. We also find that there were no biases in the item response rates across the experimental and control conditions. RCTs that involve field survey responses-like QCET-are potentially compromised by low response rates and how item response rates might be influenced by the control or experimental conditions. Our results show that the QCET results were not sensitive to the overall low response rate across the experimental and control conditions and the item response rates were not significantly different across the experimental and control groups. Overall, our analysis suggests that the results of QCET are robust and any biases in the survey responses do not significantly influence the main experimental findings.

How Do Politicians Attribute Bureaucratic Responsibility for Performance? Negativity Bias and Interest Group Advocacy

DEFF Research Database (Denmark)

Nielsen, Poul A.; Moynihan, Donald P.

2017-01-01

Voters reward or punish politicians by deeming them responsible for positive and negative outcomes, but how, in turn, do politicians attribute responsibility to those who actually deliver public services? Inattention to this question renders incomplete current perspectives on democratic processes...... to attribute causal responsibility to bureaucratic leaders, but only in cases of low performance, suggesting a negativity bias in public sector responsibility attribution processes. Additionally, we offer evidence that interest group advocates influence how elected officials use performance information...... to attribute responsibility, but contingent on ideological alignment....

Placebo effect studies are susceptible to response bias and to other types of biases

DEFF Research Database (Denmark)

Hróbjartsson, Asbjørn; Kaptchuk, Ted J; Miller, Franklin G

2011-01-01

Investigations of the effect of placebo are often challenging to conduct and interpret. The history of placebo shows that assessment of its clinical significance has a real potential to be biased. We analyze and discuss typical types of bias in studies on placebo....

Power spectrum, correlation function, and tests for luminosity bias in the CfA redshift survey

Science.gov (United States)

Park, Changbom; Vogeley, Michael S.; Geller, Margaret J.; Huchra, John P.

1994-01-01

We describe and apply a method for directly computing the power spectrum for the galaxy distribution in the extension of the Center for Astrophysics Redshift Survey. Tests show that our technique accurately reproduces the true power spectrum for k greater than 0.03 h Mpc(exp -1). The dense sampling and large spatial coverage of this survey allow accurate measurement of the redshift-space power spectrum on scales from 5 to approximately 200 h(exp -1) Mpc. The power spectrum has slope n approximately equal -2.1 on small scales (lambda less than or equal 25 h(exp -1) Mpc) and n approximately -1.1 on scales 30 less than lambda less than 120 h(exp -1) Mpc. On larger scales the power spectrum flattens somewhat, but we do not detect a turnover. Comparison with N-body simulations of cosmological models shows that an unbiased, open universe CDM model (OMEGA h = 0.2) and a nonzero cosmological constant (CDM) model (OMEGA h = 0.24, lambda(sub zero) = 0.6, b = 1.3) match the CfA power spectrum over the wavelength range we explore. The standard biased CDM model (OMEGA h = 0.5, b = 1.5) fails (99% significance level) because it has insufficient power on scales lambda greater than 30 h(exp -1) Mpc. Biased CDM with a normalization that matches the Cosmic Microwave Background (CMB) anisotropy (OMEGA h = 0.5, b = 1.4, sigma(sub 8) (mass) = 1) has too much power on small scales to match the observed galaxy power spectrum. This model with b = 1 matches both Cosmic Background Explorer Satellite (COBE) and the small-scale power spect rum but has insufficient power on scales lambda approximately 100 h(exp -1) Mpc. We derive a formula for the effect of small-scale peculiar velocities on the power spectrum and combine this formula with the linear-regime amplification described by Kaiser to compute an estimate of the real-space power spectrum. Two tests reveal luminosity bias in the galaxy distribution: First, the amplitude of the pwer spectrum is approximately 40% larger for the brightest

Importance biasing quality criterion based on contribution response theory

International Nuclear Information System (INIS)

Borisov, N.M.; Panin, M.P.

2001-01-01

The report proposes a visual criterion of importance biasing both of forward and adjoint simulation. The similarity of contribution Monte Carlo and importance biasing random collision event distribution is proved. The conservation of total number of random trajectory crossings of surfaces, which separate the source and the detector is proposed as importance biasing quality criterion. The use of this criterion is demonstrated on the example of forward vs. adjoint importance biasing in gamma ray deep penetration problem. The larger amount of published data on forward field characteristics than on adjoint leads to the more accurate approximation of adjoint importance function in comparison to forward, for it adjoint importance simulation is more effective than forward. The proposed criterion indicates it visually, showing the most uniform distribution of random trajectory crossing events for the most effective importance biasing parameters and pointing to the direction of tuning importance biasing parameters. (orig.)

Non-Gaussian halo assembly bias

International Nuclear Information System (INIS)

Reid, Beth A.; Verde, Licia; Dolag, Klaus; Matarrese, Sabino; Moscardini, Lauro

2010-01-01

The strong dependence of the large-scale dark matter halo bias on the (local) non-Gaussianity parameter, f NL , offers a promising avenue towards constraining primordial non-Gaussianity with large-scale structure surveys. In this paper, we present the first detection of the dependence of the non-Gaussian halo bias on halo formation history using N-body simulations. We also present an analytic derivation of the expected signal based on the extended Press-Schechter formalism. In excellent agreement with our analytic prediction, we find that the halo formation history-dependent contribution to the non-Gaussian halo bias (which we call non-Gaussian halo assembly bias) can be factorized in a form approximately independent of redshift and halo mass. The correction to the non-Gaussian halo bias due to the halo formation history can be as large as 100%, with a suppression of the signal for recently formed halos and enhancement for old halos. This could in principle be a problem for realistic galaxy surveys if observational selection effects were to pick galaxies occupying only recently formed halos. Current semi-analytic galaxy formation models, for example, imply an enhancement in the expected signal of ∼ 23% and ∼ 48% for galaxies at z = 1 selected by stellar mass and star formation rate, respectively

Comparison of telephone with World Wide Web-based responses by parents and teens to a follow-up survey after injury.

Science.gov (United States)

Rivara, Frederick P; Koepsell, Thomas D; Wang, Jin; Durbin, Dennis; Jaffe, Kenneth M; Vavilala, Monica; Dorsch, Andrea; Roper-Caldbeck, Maria; Houseknecht, Eileen; Temkin, Nancy

2011-06-01

To identify sociodemographic factors associated with completing a follow-up survey about health status on the web versus by telephone, and to examine differences in reported health-related quality of life by method of response. Survey about child health status of 896 parents of children aged 0-17 years treated in a hospital emergency department or admitted for a traumatic brain injury or arm injury, and 227 injured adolescents aged 14-17 years. The main outcomes were characteristics of those who completed a follow-up survey on the web versus by telephone and health-related quality of life by method of response. Email addresses were provided by 76.9 percent of parents and 56.5 percent of adolescents at baseline. The survey was completed on the web by 64.9 percent of parents and 40.2 percent of adolescents through email. Parents with email access who were Blacks, Hispanics, had lower incomes, and those who were not working were less likely to choose the web mode for completing the survey. Unlike adolescents, the amount of time for parents to complete the survey online was significantly shorter than completion by telephone. Differences by survey mode were small but statistically significant in some of the six functional outcome measures examined. Survey mode was associated with several sociodemographic characteristics. Sole use of web surveys could provide biased data. © Health Research and Educational Trust.

A study on investors’ personality characteristics and behavioral biases: Conservatism bias and availability bias in the Tehran Stock Exchange

Directory of Open Access Journals (Sweden)

Mahmoud Moradi

2013-04-01

Full Text Available Most economic and finance theories are based on the assumption that during economic decision making, people would act totally rational and consider all available information. Nevertheless, behavioral finance focuses on studying of the role of psychological factors on economic participants’ behavior. The study shows that in real-world environment, people are influenced by emotional and cognitive errors and may make irrational financial decisions. In many cases, the participants of financial markets are not aware of their talents for error in decision making, so they are dissatisfied with their investments by considering some behavioral biases decisions. These decisions may often yield undesirable outcomes, which could influence economy, significantly. This paper presents a survey on the relationship between personality dimensions with behavioral biases and availability bias among investment managers in the Tehran Stock Exchange using SPSS software, descriptive and inferential statistics. The necessary data are collected through questionnaire and they are analyzed using some statistical tests. The preliminary results indicate that there is a relationship between personality dimensions and behavioral biases like conservatism bias and availability bias among the investors in the Tehran Stock Exchange.

Are Sex Effects on Ethical Decision-Making Fake or Real? A Meta-Analysis on the Contaminating Role of Social Desirability Response Bias.

Science.gov (United States)

Yang, Jianfeng; Ming, Xiaodong; Wang, Zhen; Adams, Susan M

2017-02-01

A meta-analysis of 143 studies was conducted to explore how the social desirability response bias may influence sex effects on ratings on measures of ethical decision-making. Women rated themselves as more ethical than did men; however, this sex effect on ethical decision-making was no longer significant when social desirability response bias was controlled. The indirect questioning approach was compared with the direct measurement approach for effectiveness in controlling social desirability response bias. The indirect questioning approach was found to be more effective.

Non-response weighting adjustment approach in survey sampling ...

African Journals Online (AJOL)

Hence the discussion is illustrated with real examples from surveys (in particular 2003 KDHS) conducted by Central Bureau of Statistics (CBS) - Kenya. Some suggestions are made for improving the quality of non-response weighting. Keywords: Survey non-response; non-response adjustment factors; weighting; sampling ...

Response Strategies and Response Styles in Cross-Cultural Surveys

NARCIS (Netherlands)

Morren, M.H.; Gelissen, J.P.T.M.; Vermunt, J.K.

2012-01-01

This article addresses the following research questions: Do respondents participating in cross-cultural surveys differ in their response style when responding to attitude statements? If so, are characteristics of the response process associated with their ethnicity and generation of immigration? To

Take Care Of Home And Family, Honey, And Let Me Take Care Of The Money. Gender Bias And Credit Market Barriers For Female Entrepreneurs

NARCIS (Netherlands)

Ongena, S.; Popov, A.

2013-01-01

Abstract We identify the causal effect of gender bias on access to finance. We extract an exogenous measure of gender bias from survey responses by descendants of US immigrants on questions about the role of women in society. We then investigate a detailed dataset on small business firms from 17

QUANTIFYING THE BIASES OF SPECTROSCOPICALLY SELECTED GRAVITATIONAL LENSES

International Nuclear Information System (INIS)

Arneson, Ryan A.; Brownstein, Joel R.; Bolton, Adam S.

2012-01-01

Spectroscopic selection has been the most productive technique for the selection of galaxy-scale strong gravitational lens systems with known redshifts. Statistically significant samples of strong lenses provide a powerful method for measuring the mass-density parameters of the lensing population, but results can only be generalized to the parent population if the lensing selection biases are sufficiently understood. We perform controlled Monte Carlo simulations of spectroscopic lens surveys in order to quantify the bias of lenses relative to parent galaxies in velocity dispersion, mass axis ratio, and mass-density profile. For parameters typical of the SLACS and BELLS surveys, we find (1) no significant mass axis ratio detection bias of lenses relative to parent galaxies; (2) a very small detection bias toward shallow mass-density profiles, which is likely negligible compared to other sources of uncertainty in this parameter; (3) a detection bias toward smaller Einstein radius for systems drawn from parent populations with group- and cluster-scale lensing masses; and (4) a lens-modeling bias toward larger velocity dispersions for systems drawn from parent samples with sub-arcsecond mean Einstein radii. This last finding indicates that the incorporation of velocity-dispersion upper limits of non-lenses is an important ingredient for unbiased analyses of spectroscopically selected lens samples. In general, we find that the completeness of spectroscopic lens surveys in the plane of Einstein radius and mass-density profile power-law index is quite uniform, up to a sharp drop in the region of large Einstein radius and steep mass-density profile, and hence that such surveys are ideally suited to the study of massive field galaxies.

PLUTINO DETECTION BIASES, INCLUDING THE KOZAI RESONANCE

Energy Technology Data Exchange (ETDEWEB)

Lawler, S. M.; Gladman, B. [Department of Physics and Astronomy, 6224 Agricultural Road, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)

2013-07-01

Because of their relative proximity within the trans-Neptunian region, the plutinos (objects in the 3:2 mean-motion resonance with Neptune) are numerous in flux-limited catalogs, and well-studied theoretically. We perform detailed modeling of the on-sky detection biases for plutinos, with special attention to those that are simultaneously in the Kozai resonance. In addition to the normal 3:2 resonant argument libration, Kozai plutinos also show periodic oscillations in eccentricity and inclination, coupled to the argument of perihelion ({omega}) oscillation. Due to the mean-motion resonance, plutinos avoid coming to pericenter near Neptune's current position in the ecliptic plane. Because Kozai plutinos are restricted to certain values of {omega}, perihelion always occurs out of the ecliptic plane, biasing ecliptic surveys against finding these objects. The observed Kozai plutino fraction f{sub koz}{sup obs} has been measured by several surveys, finding values between 8% and 25%, while the true Kozai plutino fraction f{sub koz}{sup true} has been predicted to be between 10% and 30% by different giant planet migration simulations. We show that f{sub koz}{sup obs} varies widely depending on the ecliptic latitude and longitude of the survey, so debiasing to find the true ratio is complex. Even a survey that covers most or all of the sky will detect an apparent Kozai fraction that is different from f{sub koz}{sup true}. We present a map of the on-sky plutino Kozai fraction that would be detected by all-sky flux-limited surveys. This will be especially important for the Panoramic Survey Telescope and Rapid Response System and Large Synoptic Survey Telescope projects, which may detect large numbers of plutinos as they sweep the sky. f{sub koz}{sup true} and the distribution of the orbital elements of Kozai plutinos may be a diagnostic of giant planet migration; future migration simulations should provide details on their resonant Kozai populations.

Subconscious detection of threat as reflected by an enhanced response bias.

Science.gov (United States)

Windmann, S; Krüger, T

1998-12-01

Neurobiological and cognitive models of unconscious information processing suggest that subconscious threat detection can lead to cognitive misinterpretations and false alarms, while conscious processing is assumed to be perceptually and conceptually accurate and unambiguous. Furthermore, clinical theories suggest that pathological anxiety results from a crude preattentive warning system predominating over more sophisticated and controlled modes of processing. We investigated the hypothesis that subconscious detection of threat in a cognitive task is reflected by enhanced "false signal" detection rather than by selectively enhanced discrimination of threat items in 30 patients with panic disorder and 30 healthy controls. We presented a tachistoscopic word-nonword discrimination task and a subsequent recognition task and analyzed the data by means of process-dissociation procedures. In line with our expectations, subjects of both groups showed more false signal detection to threat than to neutral stimuli as indicated by an enhanced response bias, whereas indices of discriminative sensitivity did not show this effect. In addition, patients with panic disorder showed a generally enhanced response bias in comparison to healthy controls. They also seemed to have processed the stimuli less elaborately and less differentially. Results are consistent with the assumption that subconscious threat detection can lead to misrepresentations of stimulus significance and that pathological anxiety is characterized by a hyperactive preattentive alarm system that is insufficiently controlled by higher cognitive processes. Copyright 1998 Academic Press.

Innocent until primed: mock jurors' racially biased response to the presumption of innocence.

Directory of Open Access Journals (Sweden)

Danielle M Young

Full Text Available BACKGROUND: Research has shown that crime concepts can activate attentional bias to Black faces. This study investigates the possibility that some legal concepts hold similar implicit racial cues. Presumption of innocence instructions, a core legal principle specifically designed to eliminate bias, may instead serve as an implicit racial cue resulting in attentional bias. METHODOLOGY/PRINCIPAL FINDINGS: The experiment was conducted in a courtroom with participants seated in the jury box. Participants first watched a video of a federal judge reading jury instructions that contained presumption of innocence instructions, or matched length alternative instructions. Immediately following this video a dot-probe task was administered to assess the priming effect of the jury instructions. Presumption of innocence instructions, but not the alternative instructions, led to significantly faster response times to Black faces when compared with White faces. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the core principle designed to ensure fairness in the legal system actually primes attention for Black faces, indicating that this supposedly fundamental protection could trigger racial stereotypes.

Convergence among Data Sources, Response Bias, and Reliability and Validity of a Structured Job Analysis Questionnaire.

Science.gov (United States)

Smith, Jack E.; Hakel, Milton D.

1979-01-01

Examined are questions pertinent to the use of the Position Analysis Questionnaire: Who can use the PAQ reliably and validly? Must one rely on trained job analysts? Can people having no direct contact with the job use the PAQ reliably and validly? Do response biases influence PAQ responses? (Author/KC)

Responsive survey design, demographic data collection, and models of demographic behavior.

Science.gov (United States)

Axinn, William G; Link, Cynthia F; Groves, Robert M

2011-08-01

To address declining response rates and rising data-collection costs, survey methodologists have devised new techniques for using process data ("paradata") to address nonresponse by altering the survey design dynamically during data collection. We investigate the substantive consequences of responsive survey design-tools that use paradata to improve the representative qualities of surveys and control costs. By improving representation of reluctant respondents, responsive design can change our understanding of the topic being studied. Using the National Survey of Family Growth Cycle 6, we illustrate how responsive survey design can shape both demographic estimates and models of demographic behaviors based on survey data. By juxtaposing measures from regular and responsive data collection phases, we document how special efforts to interview reluctant respondents may affect demographic estimates. Results demonstrate the potential of responsive survey design to change the quality of demographic research based on survey data.

Removing Malmquist bias from linear regressions

Science.gov (United States)

Verter, Frances

1993-01-01

Malmquist bias is present in all astronomical surveys where sources are observed above an apparent brightness threshold. Those sources which can be detected at progressively larger distances are progressively more limited to the intrinsically luminous portion of the true distribution. This bias does not distort any of the measurements, but distorts the sample composition. We have developed the first treatment to correct for Malmquist bias in linear regressions of astronomical data. A demonstration of the corrected linear regression that is computed in four steps is presented.

The socio-economic patterning of survey participation and non-response error in a multilevel study of food purchasing behaviour: area- and individual-level characteristics.

Science.gov (United States)

Turrell, Gavin; Patterson, Carla; Oldenburg, Brian; Gould, Trish; Roy, Marie-Andree

2003-04-01

To undertake an assessment of survey participation and non-response error in a population-based study that examined the relationship between socio-economic position and food purchasing behaviour. The study was conducted in Brisbane City (Australia) in 2000. The sample was selected using a stratified two-stage cluster design. Respondents were recruited using a range of strategies that attempted to maximise the involvement of persons from disadvantaged backgrounds: respondents were contacted by personal visit and data were collected using home-based face-to-face interviews; multiple call-backs on different days and at different times were used; and a financial gratuity was provided. Non-institutionalised residents of private dwellings located in 50 small areas that differed in their socio-economic characteristics. Rates of survey participation - measured by non-contacts, exclusions, dropped cases, response rates and completions - were similar across areas, suggesting that residents of socio-economically advantaged and disadvantaged areas were equally likely to be recruited. Individual-level analysis, however, showed that respondents and non-respondents differed significantly in their sociodemographic and food purchasing characteristics: non-respondents were older, less educated and exhibited different purchasing behaviours. Misclassification bias probably accounted for the inconsistent pattern of association between the area- and individual-level results. Estimates of bias due to non-response indicated that although respondents and non-respondents were qualitatively different, the magnitude of error associated with this differential was minimal. Socio-economic position measured at the individual level is a strong and consistent predictor of survey non-participation. Future studies that set out to examine the relationship between socio-economic position and diet need to adopt sampling strategies and data collection methods that maximise the likelihood of recruiting

Enhanced exchange bias fields for CoO/Co bilayers: influence of antiferromagnetic grains and mechanisms

Energy Technology Data Exchange (ETDEWEB)

Chang, Cheng-Hsun-Tony; Chang, Shin-Chen [Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan (China); Tsay, Jyh-Shen, E-mail: jstsay@phy.ntnu.edu.tw [Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan (China); Yao, Yeong-Der [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China)

2017-05-31

Highlights: • An antiferromagnetic grain model on exchange bias phenomena is proposed. • Grain size and grain density are considered. • For smaller grain size, the dependence of t{sub CoO} on T{sub B} showed a less pronounced variation. • An increased grain density is responsible for the enhancement in the exchange bias fields. - Abstract: The emergence and optimization of devices that can be applied to spintronics have attracted considerable interest, and both experimental and theoretical approaches have been used in studies of exchange bias phenomena. A survey of the literature indicates that great efforts have been devoted to improving exchange bias fields, while only limited attempts have been made to control the temperature dependence of exchange bias. In this study, the influence of antiferromagnetic grains on exchange bias phenomena in CoO/Co bilayers on a semiconductor surface was investigated. Based on an antiferromagnetic grain model, a correlation between grain size, grain density, blocking temperature, and the exchange bias field was established. For crystallites with a smaller median diameter, the dependence of the thickness of the CoO layer on blocking temperature showed a less pronounced variation. This is due to the larger thermal agitation of the atomic spin moments in the grain, which causes a weaker exchange coupling between atomic spin moments. The enhanced density of antiferromagnetic/ferromagnetic pinning sites resulting from an increased grain density is responsible for the enhancement in the exchange bias fields. The results reported herein provide insights into our knowledge related to controlling the temperature dependence of exchange bias and related mechanisms.

Effect of vicarious fear learning on children's heart rate responses and attentional bias for novel animals

OpenAIRE

Reynolds, G; Field, AP; Askew, C

2014-01-01

Research with children has shown that vicarious learning can result in changes to 2 of Lang's (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang's final response system) and attentional bias. The study used Askew and Field's (2007) vicarious learning procedure and demonstrated fear-related increases in children's cognitive, behavioral, and physiol...

Northern goshawk broadcast surveys: Hawk response variables and survey cost

Science.gov (United States)

Suzanne M. Joy; Richard T. Reynolds; Douglas G. Leslie

1994-01-01

We examined responses of Northern Goshawks (Accipter gentilis) to taped broadcast calls of conspecifics in tree-harvest areas and around alternate goshawk nests on Kaibab National Forest, Arizona, in 1991 and 1992. Forest areas totaling 476 km2 were systematically surveyed for goshawks. Ninety responses by adult and juvenile goshawks were elicited...

Comparison of response rates and cost-effectiveness for a community-based survey: postal, internet and telephone modes with generic or personalised recruitment approaches

Science.gov (United States)

2012-01-01

Background Epidemiological research often requires collection of data from a representative sample of the community or recruitment of specific groups through broad community approaches. The population coverage of traditional survey methods such as mail-outs to residential addresses, and telephone contact via public directories or random-digit-dialing is declining and survey response rates are falling. There is a need to explore new sampling frames and consider multiple response modes including those offered by changes in telecommunications and internet technology. Methods We evaluated response rates and cost-effectiveness for three modes of survey administration (postal invitation/postal survey, postal invitation/internet survey and postal invitation/telephone survey) and two styles of contact approach (personalised and generic) in a community survey of greywater use. Potential respondents were contacted only once, with no follow up of non-responders. Results The telephone survey produced the highest adjusted response rate (30.2%), followed by the personalised postal survey (10.5%), generic postal survey (7.5%) and then the internet survey (4.7% for the personalised approach and 2.2% for the generic approach). There were some differences in household characteristics and greywater use rates between respondents to different survey modes, and between respondents to personalised and generic approaches. These may be attributable to the differing levels of motivations needed for a response, and varying levels of interest in the survey topic among greywater users and non-users. The generic postal survey had the lowest costs per valid survey received (Australian $22.93), followed by the personalised postal survey ($24.75). Conclusions Our findings suggest that postal surveys currently remain the most economic option for population-based studies, with similar costs for personalised and generic approaches. Internet surveys may be effective for specialised groups where email

Effect of Diffusion Limitations on Multianalyte Determination from Biased Biosensor Response

Science.gov (United States)

Baronas, Romas; Kulys, Juozas; Lančinskas, Algirdas; Žilinskas, Antanas

2014-01-01

The optimization-based quantitative determination of multianalyte concentrations from biased biosensor responses is investigated under internal and external diffusion-limited conditions. A computational model of a biocatalytic amperometric biosensor utilizing a mono-enzyme-catalyzed (nonspecific) competitive conversion of two substrates was used to generate pseudo-experimental responses to mixtures of compounds. The influence of possible perturbations of the biosensor signal, due to a white noise- and temperature-induced trend, on the precision of the concentration determination has been investigated for different configurations of the biosensor operation. The optimization method was found to be suitable and accurate enough for the quantitative determination of the concentrations of the compounds from a given biosensor transient response. The computational experiments showed a complex dependence of the precision of the concentration estimation on the relative thickness of the outer diffusion layer, as well as on whether the biosensor operates under diffusion- or kinetics-limited conditions. When the biosensor response is affected by the induced exponential trend, the duration of the biosensor action can be optimized for increasing the accuracy of the quantitative analysis. PMID:24608006

Sensitivity and specificity of a digit symbol recognition trial in the identification of response bias.

Science.gov (United States)

Kim, Nancy; Boone, Kyle B; Victor, Tara; Lu, Po; Keatinge, Carolyn; Mitchell, Cary

2010-08-01

Recently published practice standards recommend that multiple effort indicators be interspersed throughout neuropsychological evaluations to assess for response bias, which is most efficiently accomplished through use of effort indicators from standard cognitive tests already included in test batteries. The present study examined the utility of a timed recognition trial added to standard administration of the WAIS-III Digit Symbol subtest in a large sample of "real world" noncredible patients (n=82) as compared with credible neuropsychology clinic patients (n=89). Scores from the recognition trial were more sensitive in identifying poor effort than were standard Digit Symbol scores, and use of an equation incorporating Digit Symbol Age-Corrected Scaled Scores plus accuracy and time scores from the recognition trial was associated with nearly 80% sensitivity at 88.7% specificity. Thus, inclusion of a brief recognition trial to Digit Symbol administration has the potential to provide accurate assessment of response bias.

Investigating Assessment Bias for Constructed Response Explanation Tasks: Implications for Evaluating Performance Expectations for Scientific Practice

Science.gov (United States)

Federer, Meghan Rector

Assessment is a key element in the process of science education teaching and research. Understanding sources of performance bias in science assessment is a major challenge for science education reforms. Prior research has documented several limitations of instrument types on the measurement of students' scientific knowledge (Liu et al., 2011; Messick, 1995; Popham, 2010). Furthermore, a large body of work has been devoted to reducing assessment biases that distort inferences about students' science understanding, particularly in multiple-choice [MC] instruments. Despite the above documented biases, much has yet to be determined for constructed response [CR] assessments in biology and their use for evaluating students' conceptual understanding of scientific practices (such as explanation). Understanding differences in science achievement provides important insights into whether science curricula and/or assessments are valid representations of student abilities. Using the integrative framework put forth by the National Research Council (2012), this dissertation aimed to explore whether assessment biases occur for assessment practices intended to measure students' conceptual understanding and proficiency in scientific practices. Using a large corpus of undergraduate biology students' explanations, three studies were conducted to examine whether known biases of MC instruments were also apparent in a CR instrument designed to assess students' explanatory practice and understanding of evolutionary change (ACORNS: Assessment of COntextual Reasoning about Natural Selection). The first study investigated the challenge of interpreting and scoring lexically ambiguous language in CR answers. The incorporation of 'multivalent' terms into scientific discourse practices often results in statements or explanations that are difficult to interpret and can produce faulty inferences about student knowledge. The results of this study indicate that many undergraduate biology majors

The Battle over Studies of Faculty Bias

Science.gov (United States)

Gravois, John

2007-01-01

The American Federation of Teachers (AFT) recently commissioned a study to review the research that finds liberal bias run amok in academe. Believing that the AFT is not a dispassionate observer of this debate, this article provides "The Chronicle of Higher Education's" survey of the genre. The studies reviewed include: (1) "Political Bias in the…

Challenging the role of social norms regarding body weight as an explanation for weight, height, and BMI misreporting biases: Development and application of a new approach to examining misreporting and misclassification bias in surveys

LENUS (Irish Health Repository)

Brestoff, Jonathan R

2011-05-18

Abstract Background Cultural pressures to be thin and tall are postulated to cause people to misreport their body weight and height towards more socially normative (i.e., desirable) values, but a paucity of direct evidence supports this idea. We developed a novel non-linear approach to examining weight, height, and BMI misreporting biases and used this approach to examine the association between socially non-normative weight and misreporting biases in adults. Methods The Survey of Lifestyles, Attitudes, and Nutrition 2007 (SLÁN 2007), a nationally representative survey of the Republic of Ireland (N = 1942 analyzed) was used. Self-reported weight (height) was classified as under-reported by ≥2.0 kg (2.0 cm), over-reported by ≥2.0 kg (2.0 cm), or accurately reported within 2.0 kg (2.0 cm) to account for technical errors of measurement and short-term fluctuations in measured weight (height). A simulation strategy was used to define self-report-based BMI as under-estimated by more than 1.40 kg\\/m2, over-estimated by more than 1.40 kg\\/m2, or accurately estimated within 1.40 kg\\/m2. Patterns of biases in self-reported weight, height, and BMI were explored. Logistic regression was used to identify factors associated with mis-estimated BMI and to calculate adjusted odds ratios (AOR) and 99% confidence intervals (99%CI). Results The patterns of bias contributing the most to BMI mis-estimation were consistently, in decreasing order of influence, (1) under-reported weight combined with over-reported height, (2) under-reported weight with accurately reported height, and (3) accurately reported weight with over-reported height. Average bias in self-report-based BMI was -1.34 kg\\/m2 overall and -0.49, -1.33, and -2.66 kg\\/m2 in normal, overweight, and obese categories, respectively. Despite the increasing degree of bias with progressively higher BMI categories, persons describing themselves as too heavy were, within any given BMI category, less likely to have under

Demonstration of zero bias responsivity in MBE grown β-Ga2O3 lateral deep-UV photodetector

Science.gov (United States)

Singh Pratiyush, Anamika; Krishnamoorthy, Sriram; Kumar, Sandeep; Xia, Zhanbo; Muralidharan, Rangarajan; Rajan, Siddharth; Nath, Digbijoy N.

2018-06-01

We demonstrate zero-bias spectral responsivity in MBE-grown β-Ga2O3 planar UV-C detector with good linearity up to optical power density of 4.6 mW cm‑2. Devices with asymmetrical metal contacts were realized on 150 nm thick β-Ga2O3 films on sapphire. The device exhibited a spectral responsivity of 1.4 mA W‑1 at 255 nm under zero-bias condition, dark current UV-to-visible rejection ratio ∼105 at 5 V. The demonstrated UV-C detector exhibited an estimated high detectivity of 2.0 × 1012 Jones at 1 V and were found to be very stable and repeatable, suggesting its potential use for focal plane arrays.

Take Care Of Home And Family, Honey, And Let Me Take Care Of The Money. Gender Bias And Credit Market Barriers For Female Entrepreneurs

OpenAIRE

Ongena, S.; Popov, A.

2013-01-01

Abstract We identify the causal effect of gender bias on access to finance. We extract an exogenous measure of gender bias from survey responses by descendants of US immigrants on questions about the role of women in society. We then investigate a detailed dataset on small business firms from 17 countries and find that the inherited component of gender bias is associated with gender-based discrimination in the credit market of the immigrants' country of origin. In particular, in countries wit...

Mood-congruent free recall bias in anxious individuals is not a consequence of response bias

OpenAIRE

Russo, Riccardo; Whittuck, Dora; Roberson, Debi; Dutton, Kevin; Georgiou, George; Fox, Elaine

2006-01-01

The status of mood-congruent free recall bias in anxious individuals was evaluated following incidental encoding of target words. Individuals with high and low levels of trait anxiety completed a modified Stroop task, which revealed an attentional bias for threat-related stimuli in anxious individuals. This group was significantly slower in naming the colour in which threat-related words were displayed compared to neutral words. In a subsequent free recall test for the words used in the modif...

The perils of straying from protocol: sampling bias and interviewer effects.

Directory of Open Access Journals (Sweden)

Carrie J Ngongo

Full Text Available Fidelity to research protocol is critical. In a contingent valuation study in an informal urban settlement in Nairobi, Kenya, participants responded differently to the three trained interviewers. Interviewer effects were present during the survey pilot, then magnified at the start of the main survey after a seemingly slight adaptation of the survey sampling protocol allowed interviewers to speak with the "closest neighbor" in the event that no one was home at a selected household. This slight degree of interviewer choice led to inferred sampling bias. Multinomial logistic regression and post-estimation tests revealed that the three interviewers' samples differed significantly from one another according to six demographic characteristics. The two female interviewers were 2.8 and 7.7 times less likely to talk with respondents of low socio-economic status than the male interviewer. Systematic error renders it impossible to determine which of the survey responses might be "correct." This experience demonstrates why researchers must take care to strictly follow sampling protocols, consistently train interviewers, and monitor responses by interview to ensure similarity between interviewers' groups and produce unbiased estimates of the parameters of interest.

A Comparison of Web-Based and Paper-Based Survey Methods: Testing Assumptions of Survey Mode and Response Cost

Science.gov (United States)

Greenlaw, Corey; Brown-Welty, Sharon

2009-01-01

Web-based surveys have become more prevalent in areas such as evaluation, research, and marketing research to name a few. The proliferation of these online surveys raises the question, how do response rates compare with traditional surveys and at what cost? This research explored response rates and costs for Web-based surveys, paper surveys, and…

A Multilevel Multidimensional Item Response Theory Model to Address the Role of Response Style on Measurement of Attitudes in PISA 2006

Science.gov (United States)

Lu, Yi

2012-01-01

Cross-national comparisons of responses to survey items are often affected by response style, particularly extreme response style (ERS). ERS varies across cultures, and has the potential to bias inferences in cross-national comparisons. For example, in both PISA and TIMSS assessments, it has been documented that when examined within countries,…

Assessment of health surveys: fitting a multidimensional graded response model.

Science.gov (United States)

Depaoli, Sarah; Tiemensma, Jitske; Felt, John M

The multidimensional graded response model, an item response theory (IRT) model, can be used to improve the assessment of surveys, even when sample sizes are restricted. Typically, health-based survey development utilizes classical statistical techniques (e.g. reliability and factor analysis). In a review of four prominent journals within the field of Health Psychology, we found that IRT-based models were used in less than 10% of the studies examining scale development or assessment. However, implementing IRT-based methods can provide more details about individual survey items, which is useful when determining the final item content of surveys. An example using a quality of life survey for Cushing's syndrome (CushingQoL) highlights the main components for implementing the multidimensional graded response model. Patients with Cushing's syndrome (n = 397) completed the CushingQoL. Results from the multidimensional graded response model supported a 2-subscale scoring process for the survey. All items were deemed as worthy contributors to the survey. The graded response model can accommodate unidimensional or multidimensional scales, be used with relatively lower sample sizes, and is implemented in free software (example code provided in online Appendix). Use of this model can help to improve the quality of health-based scales being developed within the Health Sciences.

Effectiveness of the Comalli Stroop Test as a measure of negative response bias.

Science.gov (United States)

Arentsen, Timothy J; Boone, Kyle Brauer; Lo, Tracy T Y; Goldberg, Hope E; Cottingham, Maria E; Victor, Tara L; Ziegler, Elizabeth; Zeller, Michelle A

2013-01-01

Practice guidelines recommend the use of multiple performance validity tests (PVTs) to detect noncredible performance during neuropsychological evaluations, and PVTs embedded in standard cognitive tests achieve this goal most efficiently. The present study examined the utility of the Comalli version of the Stroop Test as a measure of response bias in a large sample of "real world" noncredible patients (n = 129) as compared with credible neuropsychology clinic patients (n=233). The credible group performed significantly better than the noncredible group on all trials, but particularly on word-reading (Stroop A) and color-naming (Stroop B); cut-scores for Stroop A and Stroop B trials were associated with moderate sensitivity (49-53%) as compared to the low sensitivity found for the color interference trial (29%). Some types of diagnoses (including learning disability, severe traumatic brain injury, psychosis, and depression), very advanced age (⩾80), and lowered IQ were associated with increased rates of false positive identifications, suggesting the need for some adjustments to cut-offs in these subgroups. Despite some previous reports of an inverted Stroop effect (i.e., color-naming worse than color interference) in noncredible subjects, individual Stroop word reading and color naming trials were much more effective in identifying response bias.

Galaxy bias from the Dark Energy Survey Science Verification data: combining galaxy density maps and weak lensing maps

Energy Technology Data Exchange (ETDEWEB)

Chang, C.; Pujol, A.; Gaztañaga, E.; Amara, A.; Réfrégier, A.; Bacon, D.; Becker, M. R.; Bonnett, C.; Carretero, J.; Castander, F. J.; Crocce, M.; Fosalba, P.; Giannantonio, T.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Ross, A. J.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Cunha, C. E.; D' Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

2016-04-15

We measure the redshift evolution of galaxy bias from a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a $\\sim$116 deg$^{2}$ area of the Dark Energy Survey (DES) Science Verification data. This method was first developed in Amara et al. (2012) and later re-examined in a companion paper (Pujol et al., in prep) with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a magnitude-limited galaxy sample. We find the galaxy bias and 1$\\sigma$ error bars in 4 photometric redshift bins to be 1.33$\\pm$0.18 (z=0.2-0.4), 1.19$\\pm$0.23 (z=0.4-0.6), 0.99$\\pm$0.36 ( z=0.6-0.8), and 1.66$\\pm$0.56 (z=0.8-1.0). These measurements are consistent at the 1-2$\\sigma$ level with mea- surements on the same dataset using galaxy clustering and cross-correlation of galaxies with CMB lensing. In addition, our method provides the only $\\sigma_8$-independent constraint among the three. We forward-model the main observational effects using mock galaxy catalogs by including shape noise, photo-z errors and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

Uncertainty in the visibility mask of a survey and its effects on the clustering of biased tracers

Energy Technology Data Exchange (ETDEWEB)

Colavincenzo, M.; Monaco, P.; Borgani, S. [Dipartimento di Fisica, Università di Trieste, via G.B. Tiepolo 11, I-34131 Trieste (Italy); Sefusatti, E., E-mail: colavincenzo@oats.inaf.it, E-mail: monaco@oats.inaf.it, E-mail: emiliano.sefusatti@brera.inaf.it, E-mail: borgani@oats.inaf.it [INAF—Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Italy)

2017-03-01

The forecasted accuracy of upcoming surveys of large-scale structure cannot be achieved without a proper quantification of the error induced by foreground removal (or other systematics like 0-point photometry offset). Because these errors are highly correlated on the sky, their influence is expected to be especially important at very large scales, at and beyond the first Baryonic Acoustic Oscillation (BAO). In this work we quantify how the uncertainty in the visibility mask of a survey, that gives the survey depth in a specific sky area, influences the measured power spectrum of a sample of tracers of the density field and its covariance matrix. We start from a very large set of 10,000 catalogs of dark matter (DM) halos in periodic cosmological boxes, produced with the PINOCCHIO approximate method. To make an analytic approach feasible, we assume luminosity-independent halo bias and an idealized geometry for the visibility mask, that is constant in square tiles of physical length l ; this should be interpreted as the projection, at the observation redshift, of the angular correlation scale of the foreground residuals. We find that the power spectrum of these biased tracers can be expressed as the sum of a cosmological term, a mask term and a term involving their convolution. The mask and convolution terms scale like P ∝ l {sup 2}σ {sub A} {sup 2}, where σ {sub A} {sup 2} is the variance of the uncertainty on the visibility mask. With l = 30−100 Mpc/ h and σ {sub A} = 5−20%, the mask term can be significant at k ∼ 0.01−0.1 h /Mpc, and the convolution term can amount to ∼ 1−10% of the total. The influence of mask uncertainty on power spectrum covariance is more complicated: the coupling of the convolution term with the other two gives rise to several mixed terms, that we quantify by difference using the mock catalogs. These are found to be of the same order of the mask covariance, and to introduce non-diagonal terms at large scales. As a consequence

Attention bias modification training under working memory load increases the magnitude of change in attentional bias.

Science.gov (United States)

Clarke, Patrick J F; Branson, Sonya; Chen, Nigel T M; Van Bockstaele, Bram; Salemink, Elske; MacLeod, Colin; Notebaert, Lies

2017-12-01

Attention bias modification (ABM) procedures have shown promise as a therapeutic intervention, however current ABM procedures have proven inconsistent in their ability to reliably achieve the requisite change in attentional bias needed to produce emotional benefits. This highlights the need to better understand the precise task conditions that facilitate the intended change in attention bias in order to realise the therapeutic potential of ABM procedures. Based on the observation that change in attentional bias occurs largely outside conscious awareness, the aim of the current study was to determine if an ABM procedure delivered under conditions likely to preclude explicit awareness of the experimental contingency, via the addition of a working memory load, would contribute to greater change in attentional bias. Bias change was assessed among 122 participants in response to one of four ABM tasks given by the two experimental factors of ABM training procedure delivered either with or without working memory load, and training direction of either attend-negative or avoid-negative. Findings revealed that avoid-negative ABM procedure under working memory load resulted in significantly greater reductions in attentional bias compared to the equivalent no-load condition. The current findings will require replication with clinical samples to determine the utility of the current task for achieving emotional benefits. These present findings are consistent with the position that the addition of a working memory load may facilitate change in attentional bias in response to an ABM training procedure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identifying attentional bias and emotional response after appearance-related stimuli exposure.

Science.gov (United States)

Cho, Ara; Kwak, Soo-Min; Lee, Jang-Han

2013-01-01

The effect of media images has been regarded as a significant variable in the construction or in the activation of body images. Individuals who have a negative body image use avoidance coping strategies to minimize damage to their body image. We identified attentional biases and negative emotional responses following exposure to body stimuli. Female university students were divided into two groups based on their use of avoidance coping strategies (high-level group: high avoidance [HA]; low-group: low avoidance [LA]), and were assigned to two different conditions (exposure to thin body pictures, ET, and exposure to oversized body pictures, EO). Results showed that the HA group paid more attention to slim bodies and reported more negative emotions than the LA group, and that the EO had more negative effects than the ET. We suggest that HAs may attend more to slim bodies as a way of avoiding overweight bodies, influenced by social pressure, and in the search for a compensation of a positive emotional balance. However, attentional bias toward slim bodies can cause an upward comparison process, leading to increased body dissatisfaction, which is the main factor in the development of eating disorders (EDs). Therefore, altering avoidance coping strategies should be considered for people at risk of EDs.

Challenging emotional prejudice by changing self-concept: priming independent self-construal reduces racial in-group bias in neural responses to other's pain.

Science.gov (United States)

Wang, Chenbo; Wu, Bing; Liu, Yi; Wu, Xinhuai; Han, Shihui

2015-09-01

Humans show stronger empathy for in-group compared with out-group members' suffering and help in-group members more than out-group members. Moreover, the in-group bias in empathy and parochial altruism tend to be more salient in collectivistic than individualistic cultures. This work tested the hypothesis that modifying self-construals, which differentiate between collectivistic and individualistic cultural orientations, affects in-group bias in empathy for perceived own-race vs other-race pain. By scanning adults using functional magnetic resonance imaging, we found stronger neural activities in the mid-cingulate, left insula and supplementary motor area (SMA) in response to racial in-group compared with out-group members' pain after participants had been primed with interdependent self-construals. However, the racial in-group bias in neural responses to others' pain in the left SMA, mid-cingulate cortex and insula was significantly reduced by priming independent self-construals. Our findings suggest that shifting an individual's self-construal leads to changes of his/her racial in-group bias in neural responses to others' suffering. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Estimating Gravity Biases with Wavelets in Support of a 1-cm Accurate Geoid Model

Science.gov (United States)

Ahlgren, K.; Li, X.

2017-12-01

Systematic errors that reside in surface gravity datasets are one of the major hurdles in constructing a high-accuracy geoid model at high resolutions. The National Oceanic and Atmospheric Administration's (NOAA) National Geodetic Survey (NGS) has an extensive historical surface gravity dataset consisting of approximately 10 million gravity points that are known to have systematic biases at the mGal level (Saleh et al. 2013). As most relevant metadata is absent, estimating and removing these errors to be consistent with a global geopotential model and airborne data in the corresponding wavelength is quite a difficult endeavor. However, this is crucial to support a 1-cm accurate geoid model for the United States. With recently available independent gravity information from GRACE/GOCE and airborne gravity from the NGS Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project, several different methods of bias estimation are investigated which utilize radial basis functions and wavelet decomposition. We estimate a surface gravity value by incorporating a satellite gravity model, airborne gravity data, and forward-modeled topography at wavelet levels according to each dataset's spatial wavelength. Considering the estimated gravity values over an entire gravity survey, an estimate of the bias and/or correction for the entire survey can be found and applied. In order to assess the accuracy of each bias estimation method, two techniques are used. First, each bias estimation method is used to predict the bias for two high-quality (unbiased and high accuracy) geoid slope validation surveys (GSVS) (Smith et al. 2013 & Wang et al. 2017). Since these surveys are unbiased, the various bias estimation methods should reflect that and provide an absolute accuracy metric for each of the bias estimation methods. Secondly, the corrected gravity datasets from each of the bias estimation methods are used to build a geoid model. The accuracy of each geoid model

Usefulness of Discriminability and Response Bias Indices for the Evaluation of Recognition Memory in Mild Cognitive Impairment and Alzheimer Disease.

Science.gov (United States)

Russo, María Julieta; Cohen, Gabriela; Campos, Jorge; Martin, Maria Eugenia; Clarens, María Florencia; Sabe, Liliana; Barcelo, Ernesto; Allegri, Ricardo F

2017-01-01

Most studies examining episodic memory in Alzheimer disease (AD) have focused on patients' impaired ability to remember information. This approach provides only a partial picture of memory deficits since other factors involved are not considered. To evaluate the recognition memory performance by using a yes/no procedure to examine the effect of discriminability and response bias measures in amnestic mild cognitive impairment (a-MCI), AD dementia, and normal-aging subjects. We included 43 controls and 45 a-MCI and 51 mild AD dementia patients. Based on the proportions of correct responses (hits) and false alarms from the Rey Auditory Verbal Learning Test (RAVLT), discriminability (d') and response bias (C) indices from signal detection theory (SDT) were calculated. Results showed significant group differences for d' (F (2) = 83.26, p < 0.001), and C (F (2) = 6.05, p = 0.00). The best predictors of group membership were delayed recall and d' scores. The d' measure correctly classified subjects with 82.98% sensitivity and 91.11% specificity. a-MCI and AD dementia subjects exhibit less discrimination accuracy and more liberal response bias than controls. Furthermore, combined indices of delayed recall and discriminability from the RAVLT are effective in defining early AD. SDT may help enhance diagnostic specificity. © 2016 S. Karger AG, Basel.

Controlling for Response Bias in Self-Ratings of Personality: A Comparison of Impression Management Scales and the Overclaiming Technique.

Science.gov (United States)

Müller, Sascha; Moshagen, Morten

2018-04-12

Self-serving response distortions pose a threat to the validity of personality scales. A common approach to deal with this issue is to rely on impression management (IM) scales. More recently, the overclaiming technique (OCT) has been proposed as an alternative and arguably superior measure of such biases. In this study (N = 162), we tested these approaches in the context of self- and other-ratings using the HEXACO personality inventory. To the extent that the OCT and IM scales can be considered valid measures of response distortions, they are expected to account for inflated self-ratings in particular for those personality dimensions that are prone to socially desirable responding. However, the results show that neither the OCT nor IM account for overly favorable self-ratings. The validity of IM as a measure of response biases was further scrutinized by a substantial correlation with other-rated honesty-humility. As such, this study questions the use of both the OCT and IM to assess self-serving response distortions.

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: BIASES IN z  > 1.46 REDSHIFTS DUE TO QUASAR DIVERSITY

Energy Technology Data Exchange (ETDEWEB)

Denney, K. D.; Peterson, B. M. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Brandt, W. N.; Grier, C. J.; Trump, J. R. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Ge, J., E-mail: denney@astronomy.ohio-state.edu [Astronomy Department University of Florida 211 Bryant Space Science Center P.O. Box 112055 Gainesville, FL 32611-2055 (United States)

2016-12-10

We use the coadded spectra of 32 epochs of Sloan Digital Sky Survey (SDSS) Reverberation Mapping Project observations of 482 quasars with z  > 1.46 to highlight systematic biases in the SDSS- and Baryon Oscillation Spectroscopic Survey (BOSS)-pipeline redshifts due to the natural diversity of quasar properties. We investigate the characteristics of this bias by comparing the BOSS-pipeline redshifts to an estimate from the centroid of He ii λ 1640. He ii has a low equivalent width but is often well-defined in high-S/N spectra, does not suffer from self-absorption, and has a narrow component which, when present (the case for about half of our sources), produces a redshift estimate that, on average, is consistent with that determined from [O ii] to within the He ii and [O ii] centroid measurement uncertainties. The large redshift differences of ∼1000 km s{sup −1}, on average, between the BOSS-pipeline and He ii-centroid redshifts, suggest there are significant biases in a portion of BOSS quasar redshift measurements. Adopting the He ii-based redshifts shows that C iv does not exhibit a ubiquitous blueshift for all quasars, given the precision probed by our measurements. Instead, we find a distribution of C iv-centroid blueshifts across our sample, with a dynamic range that (i) is wider than that previously reported for this line, and (ii) spans C iv centroids from those consistent with the systemic redshift to those with significant blueshifts of thousands of kilometers per second. These results have significant implications for measurement and use of high-redshift quasar properties and redshifts, and studies based thereon.

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: BIASES IN z  > 1.46 REDSHIFTS DUE TO QUASAR DIVERSITY

International Nuclear Information System (INIS)

Denney, K. D.; Peterson, B. M.; Horne, Keith; Brandt, W. N.; Grier, C. J.; Trump, J. R.; Ho, Luis C.; Ge, J.

2016-01-01

We use the coadded spectra of 32 epochs of Sloan Digital Sky Survey (SDSS) Reverberation Mapping Project observations of 482 quasars with z  > 1.46 to highlight systematic biases in the SDSS- and Baryon Oscillation Spectroscopic Survey (BOSS)-pipeline redshifts due to the natural diversity of quasar properties. We investigate the characteristics of this bias by comparing the BOSS-pipeline redshifts to an estimate from the centroid of He ii λ 1640. He ii has a low equivalent width but is often well-defined in high-S/N spectra, does not suffer from self-absorption, and has a narrow component which, when present (the case for about half of our sources), produces a redshift estimate that, on average, is consistent with that determined from [O ii] to within the He ii and [O ii] centroid measurement uncertainties. The large redshift differences of ∼1000 km s −1 , on average, between the BOSS-pipeline and He ii-centroid redshifts, suggest there are significant biases in a portion of BOSS quasar redshift measurements. Adopting the He ii-based redshifts shows that C iv does not exhibit a ubiquitous blueshift for all quasars, given the precision probed by our measurements. Instead, we find a distribution of C iv-centroid blueshifts across our sample, with a dynamic range that (i) is wider than that previously reported for this line, and (ii) spans C iv centroids from those consistent with the systemic redshift to those with significant blueshifts of thousands of kilometers per second. These results have significant implications for measurement and use of high-redshift quasar properties and redshifts, and studies based thereon.

Bias-limited extraction of cosmological parameters

Energy Technology Data Exchange (ETDEWEB)

Shimon, Meir; Itzhaki, Nissan; Rephaeli, Yoel, E-mail: meirs@wise.tau.ac.il, E-mail: nitzhaki@post.tau.ac.il, E-mail: yoelr@wise.tau.ac.il [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

2013-03-01

It is known that modeling uncertainties and astrophysical foregrounds can potentially introduce appreciable bias in the deduced values of cosmological parameters. While it is commonly assumed that these uncertainties will be accounted for to a sufficient level of precision, the level of bias has not been properly quantified in most cases of interest. We show that the requirement that the bias in derived values of cosmological parameters does not surpass nominal statistical error, translates into a maximal level of overall error O(N{sup −½}) on |ΔP(k)|/P(k) and |ΔC{sub l}|/C{sub l}, where P(k), C{sub l}, and N are the matter power spectrum, angular power spectrum, and number of (independent Fourier) modes at a given scale l or k probed by the cosmological survey, respectively. This required level has important consequences on the precision with which cosmological parameters are hoped to be determined by future surveys: in virtually all ongoing and near future surveys N typically falls in the range 10{sup 6}−10{sup 9}, implying that the required overall theoretical modeling and numerical precision is already very high. Future redshifted-21-cm observations, projected to sample ∼ 10{sup 14} modes, will require knowledge of the matter power spectrum to a fantastic 10{sup −7} precision level. We conclude that realizing the expected potential of future cosmological surveys, which aim at detecting 10{sup 6}−10{sup 14} modes, sets the formidable challenge of reducing the overall level of uncertainty to 10{sup −3}−10{sup −7}.

Analysis of bias voltage dependent spectral response in Ga0.51In0.49P/Ga0.99In0.01As/Ge triple junction solar cell

International Nuclear Information System (INIS)

Sogabe, Tomah; Ogura, Akio; Okada, Yoshitaka

2014-01-01

Spectral response measurement plays great role in characterizing solar cell device because it directly reflects the efficiency by which the device converts the sunlight into an electrical current. Based on the spectral response results, the short circuit current of each subcell can be quantitatively determined. Although spectral response dependence on wavelength, i.e., the well-known external quantum efficiency (EQE), has been widely used in characterizing multijunction solar cell and has been well interpreted, detailed analysis of spectral response dependence on bias voltage (SR −V bias ) has not been reported so far. In this work, we have performed experimental and numerical studies on the SR −V bias for Ga 0.51 In 0.49 P/Ga 0.99 In 0.01 As/Ge triple junction solar cell. Phenomenological description was given to clarify the mechanism of operation matching point variation in SR −V bias measurements. The profile of SR−V bias curve was explained in detail by solving the coupled two-diode current-voltage characteristic transcend formula for each subcell

The relationship between social desirability bias and self-reports of health, substance use, and social network factors among urban substance users in Baltimore, Maryland.

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Latkin, Carl A; Edwards, Catie; Davey-Rothwell, Melissa A; Tobin, Karin E

2017-10-01

Social desirability response bias may lead to inaccurate self-reports and erroneous study conclusions. The present study examined the relationship between social desirability response bias and self-reports of mental health, substance use, and social network factors among a community sample of inner-city substance users. The study was conducted in a sample of 591 opiate and cocaine users in Baltimore, Maryland from 2009 to 2013. Modified items from the Marlowe-Crowne Social Desirability Scale were included in the survey, which was conducted face-to-face and using Audio Computer Self Administering Interview (ACASI) methods. There were highly statistically significant differences in levels of social desirability response bias by levels of depressive symptoms, drug use stigma, physical health status, recent opiate and cocaine use, Alcohol Use Disorders Identification Test (AUDIT) scores, and size of social networks. There were no associations between health service utilization measures and social desirability bias. In multiple logistic regression models, even after including the Center for Epidemiologic Studies Depression Scale (CES-D) as a measure of depressive symptomology, social desirability bias was associated with recent drug use and drug user stigma. Social desirability bias was not associated with enrollment in prior research studies. These findings suggest that social desirability bias is associated with key health measures and that the associations are not primarily due to depressive symptoms. Methods are needed to reduce social desirability bias. Such methods may include the wording and prefacing of questions, clearly defining the role of "study participant," and assessing and addressing motivations for socially desirable responses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bias versus bias: harnessing hindsight to reveal paranormal belief change beyond demand characteristics.

Science.gov (United States)

Kane, Michael J; Core, Tammy J; Hunt, R Reed

2010-04-01

Psychological change is difficult to assess, in part because self-reported beliefs and attitudes may be biased or distorted. The present study probed belief change, in an educational context, by using the hindsight bias to counter another bias that generally plagues assessment of subjective change. Although research has indicated that skepticism courses reduce paranormal beliefs, those findings may reflect demand characteristics (biases toward desired, skeptical responses). Our hindsight-bias procedure circumvented demand by asking students, following semester-long skepticism (and control) courses, to recall their precourse levels of paranormal belief. People typically remember themselves as previously thinking, believing, and acting as they do now, so current skepticism should provoke false recollections of previous skepticism. Given true belief change, therefore, skepticism students should have remembered themselves as having been more skeptical than they were. They did, at least about paranormal topics that were covered most extensively in the course. Our findings thus show hindsight to be useful in evaluating cognitive change beyond demand characteristics.

Students' gender bias in teaching evaluations

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Narissra Punyanunt-Carter

2015-09-01

Full Text Available The goal of this study was to investigate if there is gender bias in student evaluations. Researchers administered a modified version of the teacher evaluation forms to 58 students (male=30; female=28 in a basic introductory communications class. Half the class was instructed to fill out the survey about a male professor, and the other half a female professor. Researchers broke down the evaluation results question by question in order to give a detailed account of the findings. Results revealed that there is certainly some gender bias at work when students evaluate their instructors. It was also found that gender bias does not significantly affect the evaluations. The results align with other findings in the available literature, which point to some sort of pattern regarding gender bias in evaluations, but it still seems to be inconsequential.  DOI: 10.18870/hlrc.v5i3.234

An examination of responses to surveys among Filipino-Australian migrants.

Science.gov (United States)

Maneze, Della; Everett, Bronwyn; DiGiacomo, Michelle; Davidson, Patricia M; Salamonson, Yenna

2016-11-18

Background Surveys are frequently used to collect data. Although paper surveys are commonly used, online surveys are gaining in popularity, with the inclusion of open-ended questions (OEQs) allowing respondents to freely express their views. Little is known about how Filipino-Australian migrants respond to surveys. There is some concern about the usefulness of OEQs administered to culturally and linguistically diverse migrants, who may have limited capacity to articulate their thoughts in writing. Aim To examine the responses of Filipino-Australian migrants to a survey. Discussion A total of 552 respondents were recruited, of whom 428 (78%) completed the questionnaire online. The overall response rate to the OEQs was 69%, with higher completion rates among those given a paper-based questionnaire and those with university educations. Conclusion Filipino migrants with functional English language skills responded well to the online survey. Paper-based administration elicited more OEQ responses, which is attributed to greater interaction between participants and researchers. Those with university educations may have more capacity to express themselves in English and were therefore more likely to complete the OEQs. Implications for practice The high response rate obtained in this study suggests that among Filipino-Australian migrants who rated their English language skills and educational level highly, the translation of OEQs may not be necessary. This has important implications for resources in research. Face-to-face interaction between participants and researchers is an important strategy for increasing the rates of response to OEQs.

In Search of Motivation for the Business Survey Response Task

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Torres van Grinsven Vanessa

2014-12-01

Full Text Available Increasing reluctance of businesses to participate in surveys often leads to declining or low response rates, poor data quality and burden complaints, and suggests that a driving force, that is, the motivation for participation and accurate and timely response, is insufficient or lacking. Inspiration for ways to remedy this situation has already been sought in the psychological theory of self-determination; previous research has favored enhancement of intrinsic motivation compared to extrinsic motivation. Traditionally however, enhancing extrinsic motivation has been pervasive in business surveys. We therefore review this theory in the context of business surveys using empirical data from the Netherlands and Slovenia, and suggest that extrinsic motivation calls for at least as much attention as intrinsic motivation, that other sources of motivation may be relevant besides those stemming from the three fundamental psychological needs (competence, autonomy and relatedness, and that other approaches may have the potential to better explain some aspects of motivation in business surveys (e.g., implicit motives. We conclude with suggestions that survey organizations can consider when attempting to improve business survey response behavior.

An Analysis on the Calculation Efficiency of the Responses Caused by the Biased Adjoint Fluxes in Hybrid Monte Carlo Simulation

International Nuclear Information System (INIS)

Khuat, Quang Huy; Kim, Song Hyun; Kim, Do Hyun; Shin, Chang Ho

2015-01-01

This technique is known as Consistent Adjoint Driven Importance Sampling (CADIS) method and it is implemented in SCALE code system. In the CADIS method, adjoint transport equation has to be solved to determine deterministic importance functions. Using the CADIS method, a problem was noted that the biased adjoint flux estimated by deterministic methods can affect the calculation efficiency and error. The biases of adjoint function are caused by the methodology, calculation strategy, tolerance of result calculated by the deterministic method and inaccurate multi-group cross section libraries. In this paper, a study to analyze the influence of the biased adjoint functions into Monte Carlo computational efficiency is pursued. In this study, a method to estimate the calculation efficiency was proposed for applying the biased adjoint fluxes in the CADIS approach. For a benchmark problem, the responses and FOMs using SCALE code system were evaluated as applying the adjoint fluxes. The results show that the biased adjoint fluxes significantly affects the calculation efficiencies

Measurement error in income and schooling, and the bias of linear estimators

DEFF Research Database (Denmark)

Bingley, Paul; Martinello, Alessandro

The characteristics of measurement error determine the bias of linear estimators. We propose a method for validating economic survey data allowing for measurement error in the validation source, and we apply this method by validating Survey of Health, Ageing and Retirement in Europe (SHARE) data...... with Danish administrative registers. We find that measurement error in surveys is classical for annual gross income but non-classical for years of schooling, causing a 21% amplification bias in IV estimators of returns to schooling. Using a 1958 Danish schooling reform, we contextualize our result...

The effectiveness of a monetary incentive offer on survey response rates and response completeness in a longitudinal study.

Science.gov (United States)

Yu, Shengchao; Alper, Howard E; Nguyen, Angela-Maithy; Brackbill, Robert M; Turner, Lennon; Walker, Deborah J; Maslow, Carey B; Zweig, Kimberly C

2017-04-26

Achieving adequate response rates is an ongoing challenge for longitudinal studies. The World Trade Center Health Registry is a longitudinal health study that periodically surveys a cohort of ~71,000 people exposed to the 9/11 terrorist attacks in New York City. Since Wave 1, the Registry has conducted three follow-up surveys (Waves 2-4) every 3-4 years and utilized various strategies to increase survey participation. A promised monetary incentive was offered for the first time to survey non-respondents in the recent Wave 4 survey, conducted 13-14 years after 9/11. We evaluated the effectiveness of a monetary incentive in improving the response rate five months after survey launch, and assessed whether or not response completeness was compromised due to incentive use. The study compared the likelihood of returning a survey for those who received an incentive offer to those who did not, using logistic regression models. Among those who returned surveys, we also examined whether those receiving an incentive notification had higher rate of response completeness than those who did not, using negative binomial regression models and logistic regression models. We found that a $10 monetary incentive offer was effective in increasing Wave 4 response rates. Specifically, the $10 incentive offer was useful in encouraging initially reluctant participants to respond to the survey. The likelihood of returning a survey increased by 30% for those who received an incentive offer (AOR = 1.3, 95% CI: 1.1, 1.4), and the incentive increased the number of returned surveys by 18%. Moreover, our results did not reveal any significant differences on response completeness between those who received an incentive offer and those who did not. In the face of the growing challenge of maintaining a high response rate for the World Trade Center Health Registry follow-up surveys, this study showed the value of offering a monetary incentive as an additional refusal conversion strategy. Our

Bias against research on gender bias.

Science.gov (United States)

Cislak, Aleksandra; Formanowicz, Magdalena; Saguy, Tamar

2018-01-01

The bias against women in academia is a documented phenomenon that has had detrimental consequences, not only for women, but also for the quality of science. First, gender bias in academia affects female scientists, resulting in their underrepresentation in academic institutions, particularly in higher ranks. The second type of gender bias in science relates to some findings applying only to male participants, which produces biased knowledge. Here, we identify a third potentially powerful source of gender bias in academia: the bias against research on gender bias. In a bibliometric investigation covering a broad range of social sciences, we analyzed published articles on gender bias and race bias and established that articles on gender bias are funded less often and published in journals with a lower Impact Factor than articles on comparable instances of social discrimination. This result suggests the possibility of an underappreciation of the phenomenon of gender bias and related research within the academic community. Addressing this meta-bias is crucial for the further examination of gender inequality, which severely affects many women across the world.

Identifying Careless Responses in Survey Data

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Meade, Adam W.; Craig, S. Bartholomew

2012-01-01

When data are collected via anonymous Internet surveys, particularly under conditions of obligatory participation (such as with student samples), data quality can be a concern. However, little guidance exists in the published literature regarding techniques for detecting careless responses. Previously several potential approaches have been…

Twice the negativity bias and half the positivity offset: Evaluative responses to emotional information in depression.

Science.gov (United States)

Gollan, Jackie K; Hoxha, Denada; Hunnicutt-Ferguson, Kallio; Norris, Catherine J; Rosebrock, Laina; Sankin, Lindsey; Cacioppo, John

2016-09-01

Humans have the dual capacity to assign a slightly pleasant valence to neutral stimuli (the positivity offset) to encourage approach behaviors, as well as to assign a higher negative valence to unpleasant images relative to the positive valence to equally arousing and extreme pleasant images (the negativity bias) to facilitate defensive strategies. We conducted an experimental psychopathology study to examine the extent to which the negativity bias and the positivity offset differ in participants with and without major depression.. Forty-one depressed and thirty-six healthy participants were evaluated using a structured clinical interview for DSM-IV Axis I disorders, questionnaires, and a computerized task designed to measure implicit affective responses to unpleasant, neutral, and pleasant stimuli. The negativity bias was significantly higher and the positivity offset was significantly lower in depressed relative to healthy participants.. Entry criteria enrolling medication-free participants with minimal DSM-IV comorbidity may limit generalizability of the findings. This study advances our understanding of the positive and negative valence systems in depression, highlighting the irregularities in the positive valence system.. Copyright © 2015 Elsevier Ltd. All rights reserved.

Conducting Surveys and Data Collection: From Traditional to Mobile and SMS-based Surveys

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Iftikhar Alam

2014-08-01

Full Text Available Fresh, bias-free and valid data collected using different survey modes is considered an essential requirement for smooth functioning and evolution of an organization. Surveys play a major role in making in-time correct decisions and generating reports. The aim of this study is to compare and investigate state-of-the-art in different survey modes including print, email, online, mobile and SMS-based surveys. Results indicated that existing methods are neither complete nor sufficient to fulfil the overall requirements of an organization which primarily rely on surveys. Also, it shows that SMS is a dominant method for data collection due to its pervasiveness. However, existing SMS-based data collection has limitations like limited number of characters per SMS, single question per SMS and lake of multimedia support. Recent trends in data collection emphasis on data collection applications for smart phones. However, in developing countries low-end mobile devices are still extensively used which makes the data collection difficult from man in the street. The paper conclude that existing survey modes and methods should be improved to get maximum responses quickly in low cost manner. The study has contributed to the area of surveying and data collection by analysing different factors such as cost, time and response rate. The results of this study can help practitioners in creating a more successful surveying method for data collection that can be effectively used for low budget projects in developed as well as developing countries.

Factors affecting study efficiency and item non-response in health surveys in developing countries: the Jamaica national healthy lifestyle survey

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Bennett Franklyn

2007-02-01

Full Text Available Abstract Background Health surveys provide important information on the burden and secular trends of risk factors and disease. Several factors including survey and item non-response can affect data quality. There are few reports on efficiency, validity and the impact of item non-response, from developing countries. This report examines factors associated with item non-response and study efficiency in a national health survey in a developing Caribbean island. Methods A national sample of participants aged 15–74 years was selected in a multi-stage sampling design accounting for 4 health regions and 14 parishes using enumeration districts as primary sampling units. Means and proportions of the variables of interest were compared between various categories. Non-response was defined as failure to provide an analyzable response. Linear and logistic regression models accounting for sample design and post-stratification weighting were used to identify independent correlates of recruitment efficiency and item non-response. Results We recruited 2012 15–74 year-olds (66.2% females at a response rate of 87.6% with significant variation between regions (80.9% to 97.6%; p Conclusion Informative health surveys are possible in developing countries. While survey response rates may be satisfactory, item non-response was high in respect of income and sexual practice. In contrast to developed countries, non-response to questions on income is higher and has different correlates. These findings can inform future surveys.

Free Speech Tensions: Responding to Bias on College and University Campuses

Science.gov (United States)

Miller, Ryan A.; Guida, Tonia; Smith, Stella; Ferguson, S. Kiersten; Medina, Elizabeth

2018-01-01

Despite the increasing development of bias response teams on college and university campuses, little scholarship has examined these teams and, in particular, team leaders' approaches to understanding the role of free speech in responding to bias. Through semi-structured interviews, administrators who served on bias response teams at 19…

Response Styles in the Partial Credit Model

OpenAIRE

Tutz, Gerhard; Schauberger, Gunther; Berger, Moritz

2016-01-01

In the modelling of ordinal responses in psychological measurement and survey- based research, response styles that represent specific answering patterns of respondents are typically ignored. One consequence is that estimates of item parameters can be poor and considerably biased. The focus here is on the modelling of a tendency to extreme or middle categories. An extension of the Partial Credit Model is proposed that explicitly accounts for this specific response style. In contrast to exi...

Association of Unconscious Race and Social Class Bias With Vignette-Based Clinical Assessments by Medical Students

Science.gov (United States)

Haider, Adil H.; Sexton, Janel; Sriram, N.; Cooper, Lisa A.; Efron, David T.; Swoboda, Sandra; Villegas, Cassandra V.; Haut, Elliott R.; Bonds, Morgan; Pronovost, Peter J.; Lipsett, Pamela A.; Freischlag, Julie A.; Cornwell, Edward E.

2012-01-01

Context Studies involving physicians suggest that unconscious bias may be related to clinical decision making and may predict poor patient-physician interaction. The presence of unconscious race and social class bias and its association with clinical assessments or decision making among medical students is unknown. Objective To estimate unconscious race and social class bias among first-year medical students and investigate its relationship with assessments made during clinical vignettes. Design, Setting, and Participants A secure Web-based survey was administered to 211 medical students entering classes at Johns Hopkins School of Medicine, Baltimore, Maryland, in August 2009 and August 2010. The survey included the Implicit Association Test (IAT) to assess unconscious preferences, direct questions regarding students’ explicit race and social class preferences, and 8 clinical assessment vignettes focused on pain assessment, informed consent, patient reliability, and patient trust. Adjusting for student demographics, multiple logistic regression was used to determine whether responses to the vignettes were associated with unconscious race or social class preferences. Main Outcome Measures Association of scores on an established IAT for race and a novel IAT for social class with vignette responses. Results Among the 202 students who completed the survey, IAT responses were consistent with an implicit preference toward white persons among 140 students (69%, 95% CI, 61%–75%). Responses were consistent with a preference toward those in the upper class among 174 students (86%, 95% CI, 80%–90%). Assessments generally did not vary by patient race or occupation, and multivariable analyses for all vignettes found no significant relationship between implicit biases and clinical assessments. Regression coefficient for the association between pain assessment and race IAT scores was −0.49 (95% CI, −1.00 to 0.03) and for social class, the coefficient was −0.04 (95% CI

The Dark Triad and the PID-5 Maladaptive Personality Traits: Accuracy, Confidence and Response Bias in Judgments of Veracity

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Benno G. Wissing

2017-09-01

Full Text Available The Dark Triad traits—narcissism, Machiavellianism and psychopathy—have been found to be associated with intra- or interpersonal deception production frequency. This cross-sectional study (N = 207 investigated if the Dark Triad traits are also associated with deception detection accuracy, as implicated by the recent conception of a deception-general ability. To investigate associations between maladaptive personality space and deception, the PID-5 maladaptive personality traits were included to investigate if besides Machiavellianism, Detachment is negatively associated with response bias. Finally, associations between the Dark Triad traits, Antagonism, Negative Affectivity and confidence judgments were investigated. Participants watched videos of lying vs. truth-telling senders and judged the truthfulness of the statements. None of the Dark Triad traits was found to be associated with the ability to detect deception. Detachment was negatively associated with response bias. Psychopathy was associated with global confidence judgments. The results provide additional support that dark and maladaptive personality traits are associated with judgmental biases but not with accuracy in deception detection. The internal consistencies of 4 of the 8 subscales of the used personality short scales were only low and nearly sufficient (αs =0.65–0.69.

Correction of Selection Bias in Survey Data: Is the Statistical Cure Worse Than the Bias?

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Hanley, James A

2017-04-01

In previous articles in the American Journal of Epidemiology (Am J Epidemiol. 2013;177(5):431-442) and American Journal of Public Health (Am J Public Health. 2013;103(10):1895-1901), Masters et al. reported age-specific hazard ratios for the contrasts in mortality rates between obesity categories. They corrected the observed hazard ratios for selection bias caused by what they postulated was the nonrepresentativeness of the participants in the National Health Interview Study that increased with age, obesity, and ill health. However, it is possible that their regression approach to remove the alleged bias has not produced, and in general cannot produce, sensible hazard ratio estimates. First, we must consider how many nonparticipants there might have been in each category of obesity and of age at entry and how much higher the mortality rates would have to be in nonparticipants than in participants in these same categories. What plausible set of numerical values would convert the ("biased") decreasing-with-age hazard ratios seen in the data into the ("unbiased") increasing-with-age ratios that they computed? Can these values be encapsulated in (and can sensible values be recovered from) one additional internal variable in a regression model? Second, one must examine the age pattern of the hazard ratios that have been adjusted for selection. Without the correction, the hazard ratios are attenuated with increasing age. With it, the hazard ratios at older ages are considerably higher, but those at younger ages are well below one. Third, one must test whether the regression approach suggested by Masters et al. would correct the nonrepresentativeness that increased with age and ill health that I introduced into real and hypothetical data sets. I found that the approach did not recover the hazard ratio patterns present in the unselected data sets: the corrections overshot the target at older ages and undershot it at lower ages.

Effects of Personalization and Invitation Email Length on Web-Based Survey Response Rates

Science.gov (United States)

Trespalacios, Jesús H.; Perkins, Ross A.

2016-01-01

Individual strategies to increase response rate and survey completion have been extensively researched. Recently, efforts have been made to investigate a combination of interventions to yield better response rates for web-based surveys. This study examined the effects of four different survey invitation conditions on response rate. From a large…

Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality

Science.gov (United States)

Sefa, Eunice; Adimazoya, Edward Akolgo; Yartey, Emmanuel; Lenzi, Rachel; Tarpo, Cindy; Heward-Mills, Nii Lante; Lew, Katherine; Ampeh, Yvonne

2018-01-01

Introduction Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample. Materials and methods The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census. Results The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample. Conclusions The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in

Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality.

Science.gov (United States)

L'Engle, Kelly; Sefa, Eunice; Adimazoya, Edward Akolgo; Yartey, Emmanuel; Lenzi, Rachel; Tarpo, Cindy; Heward-Mills, Nii Lante; Lew, Katherine; Ampeh, Yvonne

2018-01-01

Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample. The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census. The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample. The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in comparison to household surveys. Random digit dialing of mobile

Survey research with a random digit dial national mobile phone sample in Ghana: Methods and sample quality.

Directory of Open Access Journals (Sweden)

Kelly L'Engle

Full Text Available Generating a nationally representative sample in low and middle income countries typically requires resource-intensive household level sampling with door-to-door data collection. High mobile phone penetration rates in developing countries provide new opportunities for alternative sampling and data collection methods, but there is limited information about response rates and sample biases in coverage and nonresponse using these methods. We utilized data from an interactive voice response, random-digit dial, national mobile phone survey in Ghana to calculate standardized response rates and assess representativeness of the obtained sample.The survey methodology was piloted in two rounds of data collection. The final survey included 18 demographic, media exposure, and health behavior questions. Call outcomes and response rates were calculated according to the American Association of Public Opinion Research guidelines. Sample characteristics, productivity, and costs per interview were calculated. Representativeness was assessed by comparing data to the Ghana Demographic and Health Survey and the National Population and Housing Census.The survey was fielded during a 27-day period in February-March 2017. There were 9,469 completed interviews and 3,547 partial interviews. Response, cooperation, refusal, and contact rates were 31%, 81%, 7%, and 39% respectively. Twenty-three calls were dialed to produce an eligible contact: nonresponse was substantial due to the automated calling system and dialing of many unassigned or non-working numbers. Younger, urban, better educated, and male respondents were overrepresented in the sample.The innovative mobile phone data collection methodology yielded a large sample in a relatively short period. Response rates were comparable to other surveys, although substantial coverage bias resulted from fewer women, rural, and older residents completing the mobile phone survey in comparison to household surveys. Random digit

The effects of sampling bias and model complexity on the predictive performance of MaxEnt species distribution models.

Science.gov (United States)

Syfert, Mindy M; Smith, Matthew J; Coomes, David A

2013-01-01

Species distribution models (SDMs) trained on presence-only data are frequently used in ecological research and conservation planning. However, users of SDM software are faced with a variety of options, and it is not always obvious how selecting one option over another will affect model performance. Working with MaxEnt software and with tree fern presence data from New Zealand, we assessed whether (a) choosing to correct for geographical sampling bias and (b) using complex environmental response curves have strong effects on goodness of fit. SDMs were trained on tree fern data, obtained from an online biodiversity data portal, with two sources that differed in size and geographical sampling bias: a small, widely-distributed set of herbarium specimens and a large, spatially clustered set of ecological survey records. We attempted to correct for geographical sampling bias by incorporating sampling bias grids in the SDMs, created from all georeferenced vascular plants in the datasets, and explored model complexity issues by fitting a wide variety of environmental response curves (known as "feature types" in MaxEnt). In each case, goodness of fit was assessed by comparing predicted range maps with tree fern presences and absences using an independent national dataset to validate the SDMs. We found that correcting for geographical sampling bias led to major improvements in goodness of fit, but did not entirely resolve the problem: predictions made with clustered ecological data were inferior to those made with the herbarium dataset, even after sampling bias correction. We also found that the choice of feature type had negligible effects on predictive performance, indicating that simple feature types may be sufficient once sampling bias is accounted for. Our study emphasizes the importance of reducing geographical sampling bias, where possible, in datasets used to train SDMs, and the effectiveness and essentialness of sampling bias correction within MaxEnt.

Web-based surveys as an alternative to traditional mail methods.

Science.gov (United States)

Fleming, Christopher M; Bowden, Mark

2009-01-01

Environmental economists have long used surveys to gather information about people's preferences. A recent innovation in survey methodology has been the advent of web-based surveys. While the Internet appears to offer a promising alternative to conventional survey administration modes, concerns exist over potential sampling biases associated with web-based surveys and the effect these may have on valuation estimates. This paper compares results obtained from a travel cost questionnaire of visitors to Fraser Island, Australia, that was conducted using two alternate survey administration modes; conventional mail and web-based. It is found that response rates and the socio-demographic make-up of respondents to the two survey modes are not statistically different. Moreover, both modes yield similar consumer surplus estimates.

Reducing hypothetical bias in choice experiments

DEFF Research Database (Denmark)

Ladenburg, Jacob; Olsen, Søren Bøye; Nielsen, Rasmus Christian Fejer

eliminate some of the hypothetical bias. The present paper tests an addition to Cheap Talk, an Opt-Out Reminder. The Opt-Out Reminder is an objective short script presented prior to the choice sets, prompting the respondent to choose the opt-out alternative, if he/she finds the proposed policy generated...... alternatives in a choice set too expensive. The results suggest that adding an Opt-Out Reminder to Cheap Talk can in fact reduce hypothetical bias even further and reduces some of the ineffectiveness of CT in relation to the survey bid range and experienced respondents....

Measurement of food-related approach-avoidance biases: Larger biases when food stimuli are task relevant

NARCIS (Netherlands)

Lender, A.; Meule, A.; Rinck, M.; Brockmeyer, T.; Blechert, J.

2018-01-01

Strong implicit responses to food have evolved to avoid energy depletion but contribute to overeating in today's affluent environments. The Approach-Avoidance Task (AAT) supposedly assesses implicit biases in response to food stimuli: Participants push pictures on a monitor "away" or pull them

Determination for energy response and directionality of neutron survey meters

International Nuclear Information System (INIS)

Chen Changmao; Liu Jinhua; Xie Jianlun; Su Jingling

1992-01-01

The energy response and directionality of neutron survey meter type MK7 and 2202D are determined. The reactor thermal column beam, reactor filtered beams (6 eV, 24.4 keV and 144 keV), 226 Ra-Be, 241 Am-Be, 252 Cf and its moderated sources are used for the measurement. The results shows: the survey meters are influenced obviously by the direction; the response of middle-energy region is large, the energy response of 2202D is better than MK7

Methodologies for Measuring Judicial Performance: The Problem of Bias

Directory of Open Access Journals (Sweden)

Jennifer Elek

2014-12-01

Full Text Available Concerns about gender and racial bias in the survey-based evaluations of judicial performance common in the United States have persisted for decades. Consistent with a large body of basic research in the psychological sciences, recent studies confirm that the results from these JPE surveys are systematically biased against women and minority judges. In this paper, we explain the insidious manner in which performance evaluations may be biased, describe some techniques that may help to reduce expressions of bias in judicial performance evaluation surveys, and discuss the potential problem such biases may pose in other common methods of performance evaluation used in the United States and elsewhere. We conclude by highlighting the potential adverse consequences of judicial performance evaluation programs that rely on biased measurements. Durante décadas ha habido una preocupación por la discriminación por género y racial en las evaluaciones del rendimiento judicial basadas en encuestas, comunes en Estados Unidos. De acuerdo con un gran corpus de investigación básica en las ciencias psicológicas, estudios recientes confirman que los resultados de estas encuestas de evaluación del rendimiento judicial están sistemáticamente sesgados contra las mujeres y los jueces de minorías. En este artículo se explica la manera insidiosa en que las evaluaciones de rendimiento pueden estar sesgadas, se describen algunas técnicas que pueden ayudar a reducir las expresiones de sesgo en los estudios de evaluación del rendimiento judicial, y se debate el problema potencial que estos sesgos pueden plantear en otros métodos comunes de evaluación del rendimiento utilizados en Estados Unidos y otros países. Se concluye destacando las posibles consecuencias adversas de los programas de evaluación del rendimiento judicial que se basan en mediciones sesgadas. DOWNLOAD THIS PAPER FROM SSRN: http://ssrn.com/abstract=2533937

Capturing Dynamics of Biased Attention: Are New Attention Variability Measures the Way Forward?

Directory of Open Access Journals (Sweden)

Anne-Wil Kruijt

Full Text Available New indices, calculated on data from the widely used Dot Probe Task, were recently proposed to capture variability in biased attention allocation. We observed that it remains unclear which data pattern is meant to be indicative of dynamic bias and thus to be captured by these indices. Moreover, we hypothesized that the new indices are sensitive to SD differences at the response time (RT level in the absence of bias.Randomly generated datasets were analyzed to assess properties of the Attention Bias Variability (ABV and Trial Level Bias Score (TL-BS indices. Sensitivity to creating differences in 1 RT standard deviation, 2 mean RT, and 3 bias magnitude were assessed. In addition, two possible definitions of dynamic attention bias were explored by creating differences in 4 frequency of bias switching, and 5 bias magnitude in the presence of constant switching.ABV and TL-BS indices were found highly sensitive to increasing SD at the response time level, insensitive to increasing bias, linearly sensitive to increasing bias magnitude in the presence of bias switches, and non-linearly sensitive to increasing the frequency of bias switches. The ABV index was also found responsive to increasing mean response times in the absence of bias.Recently proposed DPT derived variability indices cannot uncouple measurement error from bias variability. Significant group differences may be observed even if there is no bias present in any individual dataset. This renders the new indices in their current form unfit for empirical purposes. Our discussion focuses on fostering debate and ideas for new research to validate the potentially very important notion of biased attention being dynamic.

Implicit and Explicit Weight Bias in a National Sample of 4732 Medical Students: The Medical Student CHANGES Study

OpenAIRE

Phelan, Sean M.; Dovidio, John F.; Puhl, Rebecca M.; Burgess, Diana J.; Nelson, David B.; Yeazel, Mark W.; Hardeman, Rachel; Perry, Sylvia; van Ryn, Michelle

2014-01-01

Objective To examine the magnitude of explicit and implicit weight biases compared to biases against other groups; and identify student factors predicting bias in a large national sample of medical students. Design and Methods A web-based survey was completed by 4732 1st year medical students from 49 medical schools as part of a longitudinal study of medical education. The survey included a validated measure of implicit weight bias, the implicit association test, and 2 measures of explicit bi...

Characteristics of non-response in the Danish Health Interview Surveys, 1987-1994

DEFF Research Database (Denmark)

Kjøller, Mette; Thoning, Henrik

2005-01-01

BACKGROUND: The types and quantity of non-response in surveys influence the extent to which the results may be generalized. This study analysed trends in non-response in the Danish Health Interview Surveys from 1987 to 1994 and used the National Patient Registry to assess whether non-response bia......BACKGROUND: The types and quantity of non-response in surveys influence the extent to which the results may be generalized. This study analysed trends in non-response in the Danish Health Interview Surveys from 1987 to 1994 and used the National Patient Registry to assess whether non...... respondents before data collection but similar during and after data collection. The rate was higher during the whole period among ill or disabled non-respondents. Among people who could not be contacted during the data collection period a higher admission rate was only found immediately before and during...

Is bias in the eye of the beholder? A vignette study to assess recognition of cognitive biases in clinical case workups.

Science.gov (United States)

Zwaan, Laura; Monteiro, Sandra; Sherbino, Jonathan; Ilgen, Jonathan; Howey, Betty; Norman, Geoffrey

2017-02-01

Many authors have implicated cognitive biases as a primary cause of diagnostic error. If this is so, then physicians already familiar with common cognitive biases should consistently identify biases present in a clinical workup. The aim of this paper is to determine whether physicians agree on the presence or absence of particular biases in a clinical case workup and how case outcome knowledge affects bias identification. We conducted a web survey of 37 physicians. Each participant read eight cases and listed which biases were present from a list provided. In half the cases the outcome implied a correct diagnosis; in the other half, it implied an incorrect diagnosis. We compared the number of biases identified when the outcome implied a correct or incorrect primary diagnosis. Additionally, the agreement among participants about presence or absence of specific biases was assessed. When the case outcome implied a correct diagnosis, an average of 1.75 cognitive biases were reported; when incorrect, 3.45 biases (F=71.3, p<0.00001). Individual biases were reported from 73% to 125% more often when an incorrect diagnosis was implied. There was no agreement on presence or absence of individual biases, with κ ranging from 0.000 to 0.044. Individual physicians are unable to agree on the presence or absence of individual cognitive biases. Their judgements are heavily influenced by hindsight bias; when the outcome implies a diagnostic error, twice as many biases are identified. The results present challenges for current error reduction strategies based on identification of cognitive biases. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Living with Smartphones: Does Completion Device Affect Survey Responses?

Science.gov (United States)

Lambert, Amber D.; Miller, Angie L.

2015-01-01

With the growing reliance on tablets and smartphones for internet access, understanding the effects of completion device on online survey responses becomes increasing important. This study uses data from the Strategic National Arts Alumni Project, a multi-institution online alumni survey designed to obtain knowledge of arts education, to explore…

Bias in Examination Test Banks that Accompany Cost Accounting Texts.

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Clute, Ronald C.; McGrail, George R.

1989-01-01

Eight text banks that accompany cost accounting textbooks were evaluated for the presence of bias in the distribution of correct responses. All but one were found to have considerable bias, and three of eight were found to have significant choice bias. (SK)

Self-Presentation Bias in Surveys of Teachers' Educational Technology Practices

Science.gov (United States)

Kopcha, Theodore J.; Sullivan, Howard

2007-01-01

This study investigated self-presentation bias in the self-reports of teachers about their practices in six topic areas in educational technology (Instructional Design, Assessment, Learner-Centered Instruction, Curriculum Alignment, Attitudes about Computers, and Use of Computers with Students). Subjects were 50 middle-school teachers. Data were…

Lax decision criteria lead to negativity bias: evidence from the emotional stroop task.

Science.gov (United States)

Liu, Guofang; Xin, Ziqiang; Lin, Chongde

2014-06-01

Negativity bias means that negative information is usually given more emphasis than comparable positive information. Under signal detection theory, recent research found that people more frequently and incorrectly identify negative task-related words as having been presented originally than positive words, even when they were not presented. That is, people have lax decision criteria for negative words. However, the response biases for task-unrelated negative words and for emotionally important words are still unclear. This study investigated response bias for these two kinds of words. Study 1 examined the response bias for task-unrelated negative words using an emotional Stroop task. Proportions of correct recognition to negative and positive words were assessed by non-parametric signal detection analysis. Participants have lower (i.e., more lax) decision criteria for task-unrelated negative words than for positive words. Study 2 supported and expanded this result by investigating participants' response bias for highly emotional words. Participants have lower decision criteria for highly emotional words than for less emotional words. Finally, possible evolutionary sources of the response bias were discussed.

Analysis of bias voltage dependent spectral response in Ga{sub 0.51}In{sub 0.49}P/Ga{sub 0.99}In{sub 0.01}As/Ge triple junction solar cell

Energy Technology Data Exchange (ETDEWEB)

Sogabe, Tomah, E-mail: Sogabe@mbe.rcast.u-tokyo.ac.jp; Ogura, Akio; Okada, Yoshitaka [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo 4-6-1 Komaba, Meguro-ku, Tokyo 153-8504 (Japan)

2014-02-21

Spectral response measurement plays great role in characterizing solar cell device because it directly reflects the efficiency by which the device converts the sunlight into an electrical current. Based on the spectral response results, the short circuit current of each subcell can be quantitatively determined. Although spectral response dependence on wavelength, i.e., the well-known external quantum efficiency (EQE), has been widely used in characterizing multijunction solar cell and has been well interpreted, detailed analysis of spectral response dependence on bias voltage (SR −V{sub bias}) has not been reported so far. In this work, we have performed experimental and numerical studies on the SR −V{sub bias} for Ga{sub 0.51}In{sub 0.49}P/Ga{sub 0.99}In{sub 0.01}As/Ge triple junction solar cell. Phenomenological description was given to clarify the mechanism of operation matching point variation in SR −V{sub bias} measurements. The profile of SR−V{sub bias} curve was explained in detail by solving the coupled two-diode current-voltage characteristic transcend formula for each subcell.

A dynamic-biased dual-loop-feedback CMOS LDO regulator with fast transient response

International Nuclear Information System (INIS)

Wang Han; Sun Maomao

2014-01-01

This paper presents a low-dropout regulator (LDO) for portable applications with dual-loop feedback and a dynamic bias circuit. The dual-loop feedback structure is adopted to reduce the output voltage spike and the response time of the LDO. The dynamic bias circuit enhances the slew rate at the gate of the power transistor. In addition, an adaptive miller compensation technique is employed, from which a single pole system is realized and over a 59° phase margin is achieved under the full range of the load current. The proposed LDO has been implemented in a 0.6-μm CMOS process. From the experimental results, the regulator can operate with a minimum dropout voltage of 200 mV at a maximum 300 mA load and I Q of 113 μA. The line regulation and load regulation are improved to 0.1 mV/V and 3.4 μV/mA due to the sufficient loop gain provided by the dual feedback loops. Under a full range load current step, the voltage spikes and the recovery time of the proposed LDO is reduced to 97 mV and 0.142 μs respectively. (semiconductor integrated circuits)

Non-Response in Student Surveys: The Role of Demographics, Engagement and Personality

Science.gov (United States)

Porter, Stephen R.; Whitcomb, Michael E.

2005-01-01

What causes a student to participate in a survey? This paper looks at participation across multiple surveys to understand survey non-response; by using multiple surveys we minimize the impact of survey salience. Students at a selective liberal arts college were administered four different surveys throughout the 2002-2003 academic year, and we use…

Striatal intrinsic reinforcement signals during recognition memory: relationship to response bias and dysregulation in schizophrenia

Directory of Open Access Journals (Sweden)

Daniel H Wolf

2011-12-01

Full Text Available Ventral striatum (VS is a critical brain region for reinforcement learning and motivation, and VS hypofunction is implicated in psychiatric disorders including schizophrenia. Providing rewards or performance feedback has been shown to activate VS. Intrinisically motivated subjects performing challenging cognitive tasks are likely to engage reinforcement circuitry even in the absence of external feedback or incentives. However, such intrinsic reinforcement responses have received little attention, have not been examined in relation to behavioral performance, and have not been evaluated for impairment in neuropsychiatric disorders such as schizophrenia. Here we used fMRI to examine a challenging 'old' vs. 'new' visual recognition task in healthy subjects and patients with schizophrenia. Targets were unique fractal stimuli previously presented as salient distractors in a visual oddball task, producing incidental memory encoding. Based on the prediction error theory of reinforcement learning, we hypothesized that correct target recognition would activate VS in controls, and that this activation would be greater in subjects with lower expectation of responding correctly as indexed by a more conservative response bias. We also predicted these effects would be reduced in patients with schizophrenia. Consistent with these predictions, controls activated VS and other reinforcement processing regions during correct recognition, with greater VS activation in those with a more conservative response bias. Patients did not show either effect, with significant group differences suggesting hyporesponsivity in patients to internally-generated feedback. These findings highlight the importance of accounting for intrinsic motivation and reward when studying cognitive tasks, and add to growing evidence of reward circuit dysfunction in schizophrenia that may impact cognition and function.

Affective bias as a rational response to the statistics of rewards and punishments.

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Pulcu, Erdem; Browning, Michael

2017-10-04

Affective bias, the tendency to differentially prioritise the processing of negative relative to positive events, is commonly observed in clinical and non-clinical populations. However, why such biases develop is not known. Using a computational framework, we investigated whether affective biases may reflect individuals' estimates of the information content of negative relative to positive events. During a reinforcement learning task, the information content of positive and negative outcomes was manipulated independently by varying the volatility of their occurrence. Human participants altered the learning rates used for the outcomes selectively, preferentially learning from the most informative. This behaviour was associated with activity of the central norepinephrine system, estimated using pupilometry, for loss outcomes. Humans maintain independent estimates of the information content of distinct positive and negative outcomes which may bias their processing of affective events. Normalising affective biases using computationally inspired interventions may represent a novel approach to treatment development.

Updating schematic emotional facial expressions in working memory: Response bias and sensitivity.

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Tamm, Gerly; Kreegipuu, Kairi; Harro, Jaanus; Cowan, Nelson

2017-01-01

It is unclear if positive, negative, or neutral emotional expressions have an advantage in short-term recognition. Moreover, it is unclear from previous studies of working memory for emotional faces whether effects of emotions comprise response bias or sensitivity. The aim of this study was to compare how schematic emotional expressions (sad, angry, scheming, happy, and neutral) are discriminated and recognized in an updating task (2-back recognition) in a representative sample of birth cohort of young adults. Schematic facial expressions allow control of identity processing, which is separate from expression processing, and have been used extensively in attention research but not much, until now, in working memory research. We found that expressions with a U-curved mouth (i.e., upwardly curved), namely happy and scheming expressions, favoured a bias towards recognition (i.e., towards indicating that the probe and the stimulus in working memory are the same). Other effects of emotional expression were considerably smaller (1-2% of the variance explained)) compared to a large proportion of variance that was explained by the physical similarity of items being compared. We suggest that the nature of the stimuli plays a role in this. The present application of signal detection methodology with emotional, schematic faces in a working memory procedure requiring fast comparisons helps to resolve important contradictions that have emerged in the emotional perception literature. Copyright © 2016 Elsevier B.V. All rights reserved.

Biased but in Doubt: Conflict and Decision Confidence

Science.gov (United States)

De Neys, Wim; Cromheeke, Sofie; Osman, Magda

2011-01-01

Human reasoning is often biased by intuitive heuristics. A central question is whether the bias results from a failure to detect that the intuitions conflict with traditional normative considerations or from a failure to discard the tempting intuitions. The present study addressed this unresolved debate by using people's decision confidence as a nonverbal index of conflict detection. Participants were asked to indicate how confident they were after solving classic base-rate (Experiment 1) and conjunction fallacy (Experiment 2) problems in which a cued intuitive response could be inconsistent or consistent with the traditional correct response. Results indicated that reasoners showed a clear confidence decrease when they gave an intuitive response that conflicted with the normative response. Contrary to popular belief, this establishes that people seem to acknowledge that their intuitive answers are not fully warranted. Experiment 3 established that younger reasoners did not yet show the confidence decrease, which points to the role of improved bias awareness in our reasoning development. Implications for the long standing debate on human rationality are discussed. PMID:21283574

A KiDS weak lensing analysis of assembly bias in GAMA galaxy groups

Science.gov (United States)

Dvornik, Andrej; Cacciato, Marcello; Kuijken, Konrad; Viola, Massimo; Hoekstra, Henk; Nakajima, Reiko; van Uitert, Edo; Brouwer, Margot; Choi, Ami; Erben, Thomas; Fenech Conti, Ian; Farrow, Daniel J.; Herbonnet, Ricardo; Heymans, Catherine; Hildebrandt, Hendrik; Hopkins, Andrew M.; McFarland, John; Norberg, Peder; Schneider, Peter; Sifón, Cristóbal; Valentijn, Edwin; Wang, Lingyu

2017-07-01

We investigate possible signatures of halo assembly bias for spectroscopically selected galaxy groups from the Galaxy And Mass Assembly (GAMA) survey using weak lensing measurements from the spatially overlapping regions of the deeper, high-imaging-quality photometric Kilo-Degree Survey. We use GAMA groups with an apparent richness larger than 4 to identify samples with comparable mean host halo masses but with a different radial distribution of satellite galaxies, which is a proxy for the formation time of the haloes. We measure the weak lensing signal for groups with a steeper than average and with a shallower than average satellite distribution and find no sign of halo assembly bias, with the bias ratio of 0.85^{+0.37}_{-0.25}, which is consistent with the Λ cold dark matter prediction. Our galaxy groups have typical masses of 1013 M⊙ h-1, naturally complementing previous studies of halo assembly bias on galaxy cluster scales.

Prenotification, Incentives, and Survey Modality: An Experimental Test of Methods to Increase Survey Response Rates of School Principals

Science.gov (United States)

Jacob, Robin Tepper; Jacob, Brian

2012-01-01

Teacher and principal surveys are among the most common data collection techniques employed in education research. Yet there is remarkably little research on survey methods in education, or about the most cost-effective way to raise response rates among teachers and principals. In an effort to explore various methods for increasing survey response…

Theory-Led Confirmation Bias and Experimental Persona

Science.gov (United States)

Allen, Michael

2011-01-01

Questionnaire and interview findings from a survey of three Year 8 (ages 12-13 years) science practical lessons (n = 52) demonstrate how pupils' data collection and inference making were sometimes biased by desires to confirm a personal theory. A variety of behaviours are described where learners knowingly rejected anomalies, manipulated…

Optimum survey methods when interviewing employed women.

Science.gov (United States)

Dunning, Kari; LeMasters, Grace K

2009-02-01

While survey studies have examined bias much is unknown regarding specific subpopulations, especially women workers. A population based phone, Internet, and mail survey of workplace falls during pregnancy was undertaken. Participation by industry and occupation and survey approach and bias, reliability, and incomplete data were examined. Of the 3,997 women surveyed, 71% were employed during their pregnancy. Internet responders were most likely to be employed while pregnant and to report a workplace fall at 8.8% compared to 5.8% and 6.1% for mail and phone respondents. Internet responders had the most missing employment data with company name missing for 17.9% compared to 1.3% for phone responders. Mail surveys were best for recruiting those employed in eight of nine industries, and this was especially true for service occupations. To decrease bias and increase participation, mixed approaches may be useful with particular attention for collecting occupational data. Am. J. Ind. Med. 52:105-112, 2009. (c) 2008 Wiley-Liss, Inc.

Non-response in a survey among immigrants in Denmark

DEFF Research Database (Denmark)

Deding, Mette; Fridberg, Torben; Jakobsen, Vibeke

The purpose of this paper is to study how various characteristics of respondents and interviewers affect non-response among immigrants. We use a survey conducted among immigrants in Denmark and ethnic Danes. First, we analyse the determinants of overall non-response. Second, we analyse how...... the determinants of contact and of response given contact differ. We find that characteristics of the respondents are important for the response rate – especially they are important for the probability of getting in contact with the respondent. The lower probability of response among immigrants compared to ethnic...

Approximate median regression for complex survey data with skewed response.

Science.gov (United States)

Fraser, Raphael André; Lipsitz, Stuart R; Sinha, Debajyoti; Fitzmaurice, Garrett M; Pan, Yi

2016-12-01

The ready availability of public-use data from various large national complex surveys has immense potential for the assessment of population characteristics using regression models. Complex surveys can be used to identify risk factors for important diseases such as cancer. Existing statistical methods based on estimating equations and/or utilizing resampling methods are often not valid with survey data due to complex survey design features. That is, stratification, multistage sampling, and weighting. In this article, we accommodate these design features in the analysis of highly skewed response variables arising from large complex surveys. Specifically, we propose a double-transform-both-sides (DTBS)'based estimating equations approach to estimate the median regression parameters of the highly skewed response; the DTBS approach applies the same Box-Cox type transformation twice to both the outcome and regression function. The usual sandwich variance estimate can be used in our approach, whereas a resampling approach would be needed for a pseudo-likelihood based on minimizing absolute deviations (MAD). Furthermore, the approach is relatively robust to the true underlying distribution, and has much smaller mean square error than a MAD approach. The method is motivated by an analysis of laboratory data on urinary iodine (UI) concentration from the National Health and Nutrition Examination Survey. © 2016, The International Biometric Society.

White and Black American Children’s Implicit Intergroup Bias

Science.gov (United States)

Newheiser, Anna-Kaisa; Olson, Kristina R.

2011-01-01

Despite a decline in explicit prejudice, adults and children from majority groups (e.g., White Americans) often express bias implicitly, as assessed by the Implicit Association Test. In contrast, minority-group (e.g., Black American) adults on average show no bias on the IAT. In the present research, representing the first empirical investigation of whether Black children’s IAT responses parallel those of Black adults, we examined implicit bias in 7–11-year-old White and Black American children. Replicating previous findings with adults, whereas White children showed a robust ingroup bias, Black children showed no bias. Additionally, we investigated the role of valuing status in the development of implicit bias. For Black children, explicit preference for high status predicted implicit outgroup bias: Black children who explicitly expressed high preference for rich (vs. poor) people showed an implicit preference for Whites comparable in magnitude to White children’s ingroup bias. Implications for research on intergroup bias are discussed. PMID:22184478

Hispanic nurses' experiences of bias in the workplace.

Science.gov (United States)

Moceri, Joane T

2014-01-01

The continuing issue of health inequity for Hispanics highlights the importance of retaining Hispanic nurses in the workplace. This article describes the use of short answers such as "Describe the bias you experienced" and "If a patient refused care, what was the reason given?" to increase understandings about bias through the descriptions of Hispanic nurses. In this study, bias was defined as those implicit negative stereotypes and attitudes that negatively affect judgments about, evaluations of, and actions toward others. For this qualitative component of a descriptive study employing both qualitative and quantitative methods, 111 Hispanic nurses responded to open-ended questions about experiences of bias that were included with a survey tool and demographic questionnaire. Three themes emerged: being overlooked and undervalued, having to prove competency, and living with "only-ness." Respect was an overarching concept. The written descriptions of bias provided depth and understanding to the quantitative findings. Nurse leaders are well positioned to develop and implement strategies to more effectively support Hispanic nurses and to promote nonbiased interactions in the workplace. Retaining Hispanic nurses is a vital component to address issues of health inequity for Hispanic patients.

Effects of various methodologic strategies: survey response rates among Canadian physicians and physicians-in-training.

Science.gov (United States)

Grava-Gubins, Inese; Scott, Sarah

2008-10-01

To increase the overall 2007 response rate of the National Physician Survey (NPS) from the survey's 2004 rate of response with the implementation of various methodologic strategies. Physicians were stratified to receive either a long version (12 pages) or a short version (6 pages) of the survey (38% and 62%, respectively). Mixed modes of contact were used-58% were contacted by e-mail and 42% by regular mail-with multiple modes of contact attempted for nonrespondents. The self-administered, confidential surveys were distributed in either English or French. Medical residents and students received e-mail surveys only and were offered a substantial monetary lottery incentive for completing their surveys. A professional communications firm assisted in marketing the survey and delivered advance notification of its impending distribution. Canada. A total of 62 441 practising physicians, 2627 second-year medical residents, and 9162 medical students in Canada. Of the practising physicians group, 60 811 participants were eligible and 19 239 replied, for an overall 2007 study response rate of 31.64% (compared with 35.85% in 2004). No difference in rate of response was found between the longer and shorter versions of the survey. If contacted by regular mail, the response rate was 34.1%; the e-mail group had a response rate of 29.9%. Medical student and resident response rates were 30.8% and 27.9%, respectively (compared with 31.2% and 35.6% in 2004). Despite shortening the questionnaires, contacting more physicians by e-mail, and enhancing marketing and follow-up, the 2007 NPS response rate for practising physicians did not surpass the 2004 NPS response rate. Offering a monetary lottery incentive to medical residents and students was also unsuccessful in increasing their response rates. The role of surveys in gathering information from physicians and physicians-in-training remains problematic. Researchers need to investigate alternative strategies for achieving higher rates of

Unconscious race and social class bias among acute care surgical clinicians and clinical treatment decisions.

Science.gov (United States)

Haider, Adil H; Schneider, Eric B; Sriram, N; Dossick, Deborah S; Scott, Valerie K; Swoboda, Sandra M; Losonczy, Lia; Haut, Elliott R; Efron, David T; Pronovost, Peter J; Lipsett, Pamela A; Cornwell, Edward E; MacKenzie, Ellen J; Cooper, Lisa A; Freischlag, Julie A

2015-05-01

Significant health inequities persist among minority and socially disadvantaged patients. Better understanding of how unconscious biases affect clinical decision making may help to illuminate clinicians' roles in propagating disparities. To determine whether clinicians' unconscious race and/or social class biases correlate with patient management decisions. We conducted a web-based survey among 230 physicians from surgery and related specialties at an academic, level I trauma center from December 1, 2011, through January 31, 2012. We administered clinical vignettes, each with 3 management questions. Eight vignettes assessed the relationship between unconscious bias and clinical decision making. We performed ordered logistic regression analysis on the Implicit Association Test (IAT) scores and used multivariable analysis to determine whether implicit bias was associated with the vignette responses. Differential response times (D scores) on the IAT as a surrogate for unconscious bias. Patient management vignettes varied by patient race or social class. Resulting D scores were calculated for each management decision. In total, 215 clinicians were included and consisted of 74 attending surgeons, 32 fellows, 86 residents, 19 interns, and 4 physicians with an undetermined level of education. Specialties included surgery (32.1%), anesthesia (18.1%), emergency medicine (18.1%), orthopedics (7.9%), otolaryngology (7.0%), neurosurgery (7.0%), critical care (6.0%), and urology (2.8%); 1.9% did not report a departmental affiliation. Implicit race and social class biases were present in most respondents. Among all clinicians, mean IAT D scores for race and social class were 0.42 (95% CI, 0.37-0.48) and 0.71 (95% CI, 0.65-0.78), respectively. Race and class scores were similar across departments (general surgery, orthopedics, urology, etc), race, or age. Women demonstrated less bias concerning race (mean IAT D score, 0.39 [95% CI, 0.29-0.49]) and social class (mean IAT D score

Does Specialty Bias Trump Evidence in the Management of High-risk Prostate Cancer?

Science.gov (United States)

Kishan, Amar U; Duchesne, Gillian; Wang, Pin-Chieh; Rwigema, Jean-Claude M; Saigal, Christopher; Rettig, Matthew; Steinberg, Michael L; King, Christopher R

2018-06-01

The objective was to query how specialty influences treatment recommendations for high-risk prostate cancer in 3 clinical settings: upfront management, postoperative management, and management of biochemical recurrences (BCRs) after radiotherapy (RT). We hypothesized that specialty bias would manifest in all settings, trumping available evidence. A survey of practicing urologists and radiation oncologists was distributed through electronic mail. Questions pertained to upfront management, postoperative treatment, and local salvage for postradiation BCRs. The associations between 26 selected categorical responses and specialty were assessed using multivariate logistic regression. Training level/expertise, practice setting, percentage of consultation caseload consisting of prostate cancer, and nationality were set as effect modifiers. One thousand two hundred fifty-three physicians (846 radiation oncologists and 407 urologists) completed the survey. Radiation oncologists were more likely to recommend adjuvant RT and consider it to be underutilized, and more likely to recommend salvage RT at lower prostate-specific antigen thresholds (P<0.0001). Urologists were more likely to recommend salvage radical prostatectomy or cryoablation for local salvage after RT, whereas radiation oncologists were more likely to recommend RT-based modalities and more likely to report that local salvage was underutilized after RT (P<0.0001). Urologists were more likely to report that upfront radical prostatectomy was a better definitive treatment (P<0.0001), whereas radiation oncologists were more likely to report the opposite (P=0.005). Specialty biases permeate recommendations for upfront management and management in the postoperative and post-RT BCR setting, irrespective of available evidence. These data reveal the critical need for multidisciplinary clinics and cross-specialty training as potential solutions for overcoming specialty bias.

Determinación de sesgo de no respuesta en una encuesta probabilística de hogares de comportamiento sexual con personas del mismo género Assessment of non-response bias in a probability household survey of male same-gender sexual behavior

Directory of Open Access Journals (Sweden)

José Antonio Izazola-Licea

2000-04-01

encuesta. La selección cuidadosa del personal de campo y la capacitación de los entrevistadores podría haber coadyuvado en minimizar el sesgo potencial.OBJECTIVE: To assess non-participation bias in a survey of male sexual behavior. MATERIAL AND METHODS: A household survey was carried out in 19921993 using a probability sampling frame in Mexico City. Demographic variables were available for all eligible men. The extent of non-participation bias was estimated using a version of the Heckman method, which utilizes two equations, one to predict participation and the other to predict reports of same-gender sexual behavior. RESULTS: A total of 8 068 of the 13 713 eligible men completed a face-to-face questionnaire (response rate 59%; 173 men (2.1% reported bisexual behavior in their lifetime, and 37 (0.4% reported only male partners. Survey participation was predicted using demographic variables: 67% of the observations were correctly predicted by a probit regression model: 82% of participants and 53% of non-participants (pseudo-r²=0.13. Same-gender sexual behavior was predicted by variables indicating attachment to gay/bisexual social networks, history of sexually transmitted diseases, positive attitudes towards gay and bisexual males, and lack of support from male relatives. Ninety-seven per cent of the cases was correctly predicted by the probit model (pseudo-r²=0.14. The correlation between these two equations was not statistically significant. CONCLUSIONS: These results indicate that prevalence estimates of same-gender sexual behavior among Mexico City men were not biased by selective survey participation. Careful selection and training of household interviewers may have assisted in minimizing potential bias.

In Search of Motivation for the Business Survey Response Task

NARCIS (Netherlands)

Torres van Grinsven, Vanessa; Bolko, Irena; Bavdaz, Mojca

2014-01-01

Increasing reluctance of businesses to participate in surveys often leads to declining or low response rates, poor data quality and burden complaints, and suggests that a driving force, that is, the motivation for participation and accurate and timely response, is insufficient or lacking.

Anticipated Regret and Omission Bias in HPV Vaccination Decisions

DEFF Research Database (Denmark)

Jensen, Niels Holm

2017-01-01

This study investigated effects of anticipated regret on parents’ HPV vaccination intentions and effects of omission bias on HPV vaccination intentions and vaccine uptake. An online survey was completed by 851 parents of adolescent girls in Denmark, a country where HPV vaccine safety is currently...... heavily debated. Multivariate regression analyses revealed anticipated inaction regret as a significant positive predictor of vaccination intentions, and, anticipated action regret as a significant negative predictor of vaccination intentions. Multivariate analyses also revealed omission bias...... in a hypothetical vaccination vignette as a significant negative predictor of HPV vaccination intention as well as vaccine uptake. Finally, the study tested effects of anticipated regret and omission bias on evaluations of two extisting Danish pro-vaccine campaign videos. Here, the result revealed anticipated...

Systematic biases in human heading estimation.

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Luigi F Cuturi

Full Text Available Heading estimation is vital to everyday navigation and locomotion. Despite extensive behavioral and physiological research on both visual and vestibular heading estimation over more than two decades, the accuracy of heading estimation has not yet been systematically evaluated. Therefore human visual and vestibular heading estimation was assessed in the horizontal plane using a motion platform and stereo visual display. Heading angle was overestimated during forward movements and underestimated during backward movements in response to both visual and vestibular stimuli, indicating an overall multimodal bias toward lateral directions. Lateral biases are consistent with the overrepresentation of lateral preferred directions observed in neural populations that carry visual and vestibular heading information, including MSTd and otolith afferent populations. Due to this overrepresentation, population vector decoding yields patterns of bias remarkably similar to those observed behaviorally. Lateral biases are inconsistent with standard bayesian accounts which predict that estimates should be biased toward the most common straight forward heading direction. Nevertheless, lateral biases may be functionally relevant. They effectively constitute a perceptual scale expansion around straight ahead which could allow for more precise estimation and provide a high gain feedback signal to facilitate maintenance of straight-forward heading during everyday navigation and locomotion.

Effects of Mentioning the Incentive Prize in the Email Subject Line on Survey Response

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Robert Janke

2014-03-01

Full Text Available Objective – This study examined the effects that mentioning the survey incentive prize in the subject line of a reminder email had on the response rate and data quality. To date, manipulation of the subject line, specifically in terms of mentioning the incentive prize, has received limited attention in the survey design literature. Methods – The delivery of the survey invitation is discussed in terms of the timing of the launch and reminder emails. Particular emphasis is given to the design of the email subject line and justification of the format. Weekly response rates from four LibQUAL+TM surveys were compared. In addition, weekly responses for one year were analyzed using SPSS to investigate if there were any between means differences in terms of three elements of data quality. The three elements were: length of time it took to complete the survey, the number of core questions with an N/A response, and the number of illogical responses where minimum scores were higher than desired. Results – The response rates for the second week were grouped together based on the presence or absence of the subject line manipulation. There was a significant difference between these means (4.75%, p 0.033. There was no statistical difference in regards to the measures of data quality as determined by a one-way ANOVA test. Conclusions – Reminding survey participants with an email that mentions the incentive prize in the subject line appears to increase response rates with no deleterious effects on data quality. The results of this investigation are encouraging, and those running the LibQUAL+TM survey in their universities should consider implementing this method to increase response rates. Further research to replicate these findings in other contexts and using an experimental design would be beneficial.

Biased sampling, over-identified parameter problems and beyond

CERN Document Server

Qin, Jing

2017-01-01

This book is devoted to biased sampling problems (also called choice-based sampling in Econometrics parlance) and over-identified parameter estimation problems. Biased sampling problems appear in many areas of research, including Medicine, Epidemiology and Public Health, the Social Sciences and Economics. The book addresses a range of important topics, including case and control studies, causal inference, missing data problems, meta-analysis, renewal process and length biased sampling problems, capture and recapture problems, case cohort studies, exponential tilting genetic mixture models etc. The goal of this book is to make it easier for Ph. D students and new researchers to get started in this research area. It will be of interest to all those who work in the health, biological, social and physical sciences, as well as those who are interested in survey methodology and other areas of statistical science, among others. .

Non-response in a cross-sectional study of respiratory health in Norway

OpenAIRE

Abrahamsen, Regine; Svendsen, Martin Veel; Henneberger, Paul K; Gundersen, G?lin Finckenhagen; Tor?n, Kjell; Kongerud, Johny; Fell, Anne Kristin M?ller

2016-01-01

Objectives Declining participation in epidemiological studies has been reported in recent decades and may lead to biased prevalence estimates and selection bias. The aim of the study was to identify possible causes and effects of non-response in a population-based study of respiratory health in Norway. Design The Telemark study is a longitudinal study that began with a cross-sectional survey in 2013. Setting In 2013, a random sample of 50?000 inhabitants aged 16?50?years, living in Telemark c...

Primordial non-Gaussianity from LAMOST surveys

International Nuclear Information System (INIS)

Gong Yan; Wang Xin; Chen Xuelei; Zheng Zheng

2010-01-01

The primordial non-Gaussianity (PNG) in the matter density perturbation is a very powerful probe of the physics of the very early Universe. The local PNG can induce a distinct scale-dependent bias on the large scale structure distribution of galaxies and quasars, which could be used for constraining it. We study the detection limits of PNG from the surveys of the LAMOST telescope. The cases of the main galaxy survey, the luminous red galaxy (LRG) survey, and the quasar survey of different magnitude limits are considered. We find that the Main1 sample (i.e. the main galaxy survey which is one magnitude deeper than the SDSS main galaxy survey, or r NL are |f NL | NL | NL | is between 50 and 103, depending on the magnitude limit of the survey. With Planck-like priors on cosmological parameters, the quasar survey with g NL | < 43 (2σ). We also discuss the possibility of further tightening the constraint by using the relative bias method proposed by Seljak.

Reliability of Nationwide Prevalence Estimates of Dementia: A Critical Appraisal Based on Brazilian Surveys.

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Flávio Chaimowicz

Full Text Available The nationwide dementia prevalence is usually calculated by applying the results of local surveys to countries' populations. To evaluate the reliability of such estimations in developing countries, we chose Brazil as an example. We carried out a systematic review of dementia surveys, ascertained their risk of bias, and present the best estimate of occurrence of dementia in Brazil.We carried out an electronic search of PubMed, Latin-American databases, and a Brazilian thesis database for surveys focusing on dementia prevalence in Brazil. The systematic review was registered at PROSPERO (CRD42014008815. Among the 35 studies found, 15 analyzed population-based random samples. However, most of them utilized inadequate criteria for diagnostics. Six studies without these limitations were further analyzed to assess the risk of selection, attrition, outcome and population bias as well as several statistical issues. All the studies presented moderate or high risk of bias in at least two domains due to the following features: high non-response, inaccurate cut-offs, and doubtful accuracy of the examiners. Two studies had limited external validity due to high rates of illiteracy or low income. The three studies with adequate generalizability and the lowest risk of bias presented a prevalence of dementia between 7.1% and 8.3% among subjects aged 65 years and older. However, after adjustment for accuracy of screening, the best available evidence points towards a figure between 15.2% and 16.3%.The risk of bias may strongly limit the generalizability of dementia prevalence estimates in developing countries. Extrapolations that have already been made for Brazil and Latin America were based on a prevalence that should have been adjusted for screening accuracy or not used at all due to severe bias. Similar evaluations regarding other developing countries are needed in order to verify the scope of these limitations.

Bias and frequency response of the permeability of CoZrNb/SiO2 multilayers

International Nuclear Information System (INIS)

Louis, E.; Jeong, I.S.; Walser, R.M.

1990-01-01

Compared to single-layer films, CoZrNb/SiO 2 multilayers with amorphous, soft magnetic films exhibit increased high-frequency response (to about 100 MHz) that is not understood. We studied single and multilayer films in this system and observed three distinct types of magnetic bias and frequency responses (phases I--III). The high-frequency responses of phase II and III films were reduced from that of phase I. Phase changes were produced in the single-layer amorphous CoZrNb films by varying the film thickness, and in double-layer (N=2) and multilayer (N>2) films by varying the magnetic layer thickness. The phase boundaries in the former were shifted by magnetostatic coupling of the perpendicular component of M. These studies indicated that phase I films had uniform planar magnetizations, while phase II and III films had perpendicular components. The results are summarized in the form of a phase diagram (film thickness versus inverse film separation), which suggests that the frequency response of multilayer thin films is enhanced when the individual magnetic layers are sufficiently thin to insure a planar magnetization (phase I)

Attrition in the Austrian Generations and Gender Survey: Is there a bias by fertility-relevant aspects?

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Isabella Buber-Ennser

2014-08-01

Full Text Available Background: In longitudinal research the loss of sample members between waves is a possible source of bias. It is therefore crucial to analyse attrition. Objective: This paper analyses attrition in a longitudinal study on family and fertility, by distinguishing between attrition due to non-contact and attrition due to non-cooperation. Methods: Based on the first two waves of the Austrian Generations and Gender Survey, the two components of attrition are studied separately by using bivariate as well as multivariate methods. Moreover, overall dropout - the combination of both components - isanalysed. Apart from various socio-economic characteristics and data collection information, the study focuses on fertility-relevant variables such as fecundity, fertility intentions, sexual orientation, and traditional attitudes. Results: Fecundity, fertility intentions, and homosexual relationships are associated with higher attrition due to non-cooperation in bivariate analyses, but have no explanatory power inthe multivariate model. Pregnancy and traditional attitudes towards marriage are associated with significantly lower attrition due to non-cooperation in the multivariate context. Overall dropout is significantly lower only among persons with traditionalattitudes towards marriage, although small in size and statistical significance. Moreover, various individual and regional characteristics are significantly associated with dropout, with differences between attrition due to non-contact and attrition due to non-cooperation. Conclusions: Detailed insights into attrition are not only important when using longitudinal data and interpreting results, but also for the design of future data collections. The Austrian GGS panel has a relatively low dropout (22Š and is affected by a small bias towards familyoriented persons as well as less-educated respondents and persons with migrationbackgrounds, but the data can be used without concern about selectivity.

A Floquet-Green's function approach to mesoscopic transport under ac bias

International Nuclear Information System (INIS)

Wu, B H; Cao, J C

2008-01-01

The current response of a mesoscopic system under a periodic ac bias is investigated by combining the Floquet theorem and the nonequilibrium Green's function method. The band structure of the lead under ac bias is fully taken into account by using appropriate self-energies in an enlarged Floquet space. Both the retarded and lesser Green's functions are obtained in the Floquet basis to account for the interference and interaction effects. In addition to the external ac bias, the time-varying Coulomb interaction, which is treated at the self-consistent Hartree-Fock level, provides another internal ac field. The numerical results show that the time-varying Coulomb field yields decoherence and reduces the ringing behavior of the current response to a harmonic bias

Does the sequence of data collection influence participants' responses to closed and open-ended questions? A methodological study.

Science.gov (United States)

Covell, Christine L; Sidani, Souraya; Ritchie, Judith A

2012-06-01

The sequence used for collecting quantitative and qualitative data in concurrent mixed-methods research may influence participants' responses. Empirical evidence is needed to determine if the order of data collection in concurrent mixed methods research biases participants' responses to closed and open-ended questions. To examine the influence of the quantitative-qualitative sequence on responses to closed and open-ended questions when assessing the same variables or aspects of a phenomenon simultaneously within the same study phase. A descriptive cross-sectional, concurrent mixed-methods design was used to collect quantitative (survey) and qualitative (interview) data. The setting was a large multi-site health care centre in Canada. A convenience sample of 50 registered nurses was selected and participated in the study. Participants were randomly assigned to one of two sequences for data collection, quantitative-qualitative or qualitative-quantitative. Independent t-tests were performed to compare the two groups' responses to the survey items. Directed content analysis was used to compare the participants' responses to the interview questions. The sequence of data collection did not greatly affect the participants' responses to the closed-ended questions (survey items) or the open-ended questions (interview questions). The sequencing of data collection, when using both survey and semi-structured interviews, may not bias participants' responses to closed or open-ended questions. Additional research is required to confirm these findings. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Response rates in three opinion surveys performed through online questionnaires in the health setting].

Science.gov (United States)

Aerny Perreten, Nicole; Domínguez-Berjón, Ma Felicitas; Astray Mochales, Jenaro; Esteban-Vasallo, María D; Blanco Ancos, Luis Miguel; Lópaz Pérez, Ma Ángeles

2012-01-01

The main advantages of online questionnaires are the speed of data collection and cost savings, but response rates are usually low. This study analyzed response rates and associated factors among health professionals in three opinion surveys in the autonomous region of Madrid. The participants, length of the questionnaire and topic differed among the three surveys. The surveys were conducted by using paid Internet software. The institutional e-mail addresses of distinct groups of health professionals were used. Response rates were highest in hospitals (up to 63%) and administrative services and were lowest in primary care (less than 33%). The differences in response rates were analyzed in primary care professionals according to age, sex and professional category and only the association with age was statistically significant. None of the surveys achieved a response rate of 60%. Differences were observed according to workplace, patterns of Internet usage, and interest in the subject. Copyright © 2011 SESPAS. Published by Elsevier Espana. All rights reserved.

Evaluation of Life Events in Major Depression: Assessing Negative Emotional Bias.

Science.gov (United States)

Girz, Laura; Driver-Linn, Erin; Miller, Gregory A; Deldin, Patricia J

2017-05-01

Overly negative appraisals of negative life events characterize depression but patterns of emotion bias associated with life events in depression are not well understood. The goal of this paper is to determine under which situations emotional responses are stronger than expected given life events and which emotions are biased. Depressed (n = 16) and non-depressed (n = 14) participants (mean age = 41.4 years) wrote about negative life events involving their own actions and inactions, and rated the current emotion elicited by those events. They also rated emotions elicited by someone else's actions and inactions. These ratings were compared with evaluations provided by a second, 'benchmark' group of non-depressed individuals (n = 20) in order to assess the magnitude and direction of possible biased emotional reactions in the two groups. Participants with depression reported greater anger and disgust than expected in response to both actions and inactions, whereas they reported greater guilt, shame, sadness, responsibility and fear than expected in response to inactions. Relative to non-depressed and benchmark participants, depressed participants were overly negative in the evaluation of their own life events, but not the life events of others. A standardized method for establishing emotional bias reveals a pattern of overly negative emotion only in depressed individuals' self-evaluations, and in particular with respect to anger and disgust, lending support to claims that major depressives' evaluations represent negative emotional bias and to clinical interventions that address this bias. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Further Validation of the MMPI-2 And MMPI-2-RF Response Bias Scale: Findings from Disability and Criminal Forensic Settings

Science.gov (United States)

Wygant, Dustin B.; Sellbom, Martin; Gervais, Roger O.; Ben-Porath, Yossef S.; Stafford, Kathleen P.; Freeman, David B.; Heilbronner, Robert L.

2010-01-01

The present study extends the validation of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) and the Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF) Response Bias Scale (RBS; R. O. Gervais, Y. S. Ben-Porath, D. B. Wygant, & P. Green, 2007) in separate forensic samples composed of disability claimants and…

An Investigation of Human Inductive Biases in Causality and Probability Judgments

OpenAIRE

Yeung, Sai Wing

2011-01-01

People often makes inductive inferences that go beyond the data that are given. In order to generate these inferences, people must rely on inductive biases - constraints on learning that guide conclusion from limited data. This thesis presents a survey of three topics concerning people's inductive biases.The first part of this thesis examines people's expectations about the strengths of causes in elemental causal induction - learning about the relationship between a single cause and effect. T...

Hybrid biasing approaches for global variance reduction

International Nuclear Information System (INIS)

Wu, Zeyun; Abdel-Khalik, Hany S.

2013-01-01

A new variant of Monte Carlo—deterministic (DT) hybrid variance reduction approach based on Gaussian process theory is presented for accelerating convergence of Monte Carlo simulation and compared with Forward-Weighted Consistent Adjoint Driven Importance Sampling (FW-CADIS) approach implemented in the SCALE package from Oak Ridge National Laboratory. The new approach, denoted the Gaussian process approach, treats the responses of interest as normally distributed random processes. The Gaussian process approach improves the selection of the weight windows of simulated particles by identifying a subspace that captures the dominant sources of statistical response variations. Like the FW-CADIS approach, the Gaussian process approach utilizes particle importance maps obtained from deterministic adjoint models to derive weight window biasing. In contrast to the FW-CADIS approach, the Gaussian process approach identifies the response correlations (via a covariance matrix) and employs them to reduce the computational overhead required for global variance reduction (GVR) purpose. The effective rank of the covariance matrix identifies the minimum number of uncorrelated pseudo responses, which are employed to bias simulated particles. Numerical experiments, serving as a proof of principle, are presented to compare the Gaussian process and FW-CADIS approaches in terms of the global reduction in standard deviation of the estimated responses. - Highlights: ► Hybrid Monte Carlo Deterministic Method based on Gaussian Process Model is introduced. ► Method employs deterministic model to calculate responses correlations. ► Method employs correlations to bias Monte Carlo transport. ► Method compared to FW-CADIS methodology in SCALE code. ► An order of magnitude speed up is achieved for a PWR core model.

Issues in environmental survey design

International Nuclear Information System (INIS)

Iachan, R.

1989-01-01

Several environmental survey design issues are discussed and illustrated with surveys designed by Research Triangle Institute statisticians. Issues related to sampling and nonsampling errors are illustrated for indoor air quality surveys, radon surveys, pesticide surveys, and occupational and personal exposure surveys. Sample design issues include the use of auxiliary information (e.g. for stratification), and sampling in time. We also discuss the reduction and estimation of nonsampling errors, including nonresponse and measurement bias

Mapping neighborhood scale survey responses with uncertainty metrics

Directory of Open Access Journals (Sweden)

Charles Robert Ehlschlaeger

2016-12-01

Full Text Available This paper presents a methodology of mapping population-centric social, infrastructural, and environmental metrics at neighborhood scale. This methodology extends traditional survey analysis methods to create cartographic products useful in agent-based modeling and geographic information analysis. It utilizes and synthesizes survey microdata, sub-upazila attributes, land use information, and ground truth locations of attributes to create neighborhood scale multi-attribute maps. Monte Carlo methods are employed to combine any number of survey responses to stochastically weight survey cases and to simulate survey cases' locations in a study area. Through such Monte Carlo methods, known errors from each of the input sources can be retained. By keeping individual survey cases as the atomic unit of data representation, this methodology ensures that important covariates are retained and that ecological inference fallacy is eliminated. These techniques are demonstrated with a case study from the Chittagong Division in Bangladesh. The results provide a population-centric understanding of many social, infrastructural, and environmental metrics desired in humanitarian aid and disaster relief planning and operations wherever long term familiarity is lacking. Of critical importance is that the resulting products have easy to use explicit representation of the errors and uncertainties of each of the input sources via the automatically generated summary statistics created at the application's geographic scale.

Measuring Disparities: Bias in the SF-36v2 among Spanish-speaking Medical Patients

Science.gov (United States)

Sudano, Joseph J.; Perzynski, Adam; Love, Thomas E.; Lewis, Steven A.; Murray, Patrick M.; Huber, Gail; Ruo, Bernice; Baker, David W.

2011-01-01

Background Many national surveys have found substantial differences in self-reported overall health (SROH) between Spanish-speaking Hispanics and other racial/ethnic groups. However, because cultural and language differences may create measurement bias, it is unclear whether observed differences in SROH reflect true differences in health. Objectives This study uses a cross-sectional survey to investigate psychometric properties of the SF-36v2 for subjects across four racial/ethnic and language groups. Multi-group latent variable modeling was used to test increasingly stringent criteria for measurement equivalence. Subjects Our sample (N = 1281) included 383 non-Hispanic whites, 368 non-Hispanic blacks, 206 Hispanics interviewed in English and 324 Hispanics interviewed in Spanish recruited from outpatient medical clinics in two large urban areas. Results We found weak factorial invariance across the four groups. However, there was no strong factorial invariance. The overall fit of the model was substantially worse (change in CFI > .02, RMSEA change > .003) after requiring equal intercepts across all groups. Further comparisons established that the equality constraints on the intercepts for Spanish-speaking Hispanics were responsible for the decrement to model fit. Conclusions Observed differences between SF-36v2 scores for Spanish speaking Hispanics are systematically biased relative to the other three groups. The lack of strong invariance suggests the need for caution when comparing SF-36v2 mean scores of Spanish-speaking Hispanics with those of other groups. However, measurement equivalence testing for this study supports correlational or multivariate latent variable analyses of SF-36v2 responses across all four subgroups, since these analyses require only weak factorial invariance. PMID:21430580

A comparison of clinicians' racial biases in the United States and France.

Science.gov (United States)

Khosla, Natalia N; Perry, Sylvia P; Moss-Racusin, Corinne A; Burke, Sara E; Dovidio, John F

2018-04-13

Clinician bias contributes to racial disparities in healthcare, but its effects may be indirect and culturally specific. The present work aims to investigate clinicians' perceptions of Black versus White patients' personal responsibility for their health, whether this variable predicts racial bias against Black patients, and whether this effect differs between the U.S. and France. American (N = 83) and French (N = 81) clinicians were randomly assigned to report their impressions of an identical Black or White male patient based on a physician's notes. We measured clinicians' views of the patient's anticipated improvement and adherence to treatment and their perceptions concerning how personally responsible the patient was for his health. Whereas French clinicians did not exhibit significant racial bias on the measures of interest, American clinicians rated a hypothetical White patient, compared to an identical Black patient, as significantly more likely to improve, adhere to treatment, and be personally responsible for his health. Moreover, in the U.S., personal responsibility mediated the racial difference in expected improvement, such that as the White patient was seen as more personally responsible for his health, he was also viewed as more likely to improve. The present work indicates that American clinicians displayed less optimistic expectations for the medical treatment and health of a Black male patient, relative to a White male patient, and that this racial bias was related to their view of the Black patient as being less personally responsible for his health relative to the White patient. French clinicians did not show this pattern of racial bias, suggesting the importance of considering cultural influences for understanding racial biases in healthcare and health. Copyright © 2018 Elsevier Ltd. All rights reserved.

On a problematic procedure to manipulate response biases in recognition experiments: the case of "implied" base rates.

Science.gov (United States)

Bröder, Arndt; Malejka, Simone

2017-07-01

The experimental manipulation of response biases in recognition-memory tests is an important means for testing recognition models and for estimating their parameters. The textbook manipulations for binary-response formats either vary the payoff scheme or the base rate of targets in the recognition test, with the latter being the more frequently applied procedure. However, some published studies reverted to implying different base rates by instruction rather than actually changing them. Aside from unnecessarily deceiving participants, this procedure may lead to cognitive conflicts that prompt response strategies unknown to the experimenter. To test our objection, implied base rates were compared to actual base rates in a recognition experiment followed by a post-experimental interview to assess participants' response strategies. The behavioural data show that recognition-memory performance was estimated to be lower in the implied base-rate condition. The interview data demonstrate that participants used various second-order response strategies that jeopardise the interpretability of the recognition data. We thus advice researchers against substituting actual base rates with implied base rates.

Survey on the Contemporary Management of Intraoperative Urethral Injuries During Penile Prosthesis Implantation.

Science.gov (United States)

Sexton, Stephanie J; Granieri, Michael A; Lentz, Aaron C

2018-04-01

clean intermittent catheterization dependence. A urethral injury during penile prosthesis implantation might not mandate termination of the procedure despite classic teaching. The strength of this study is that it provides difficult to obtain epidemiologic data on the frequency and management of this clinically significant injury. Limitations include the inherent biases from a survey-based study including response bias and recall bias. The survey response rate could not be obtained. Urethral injury during penile prosthesis implantation is a rare but clinically significant risk of the procedure, with many variations in management of the injury. Termination and delayed implantation might not be necessary after injury, although long-term outcome data are difficult to obtain. Sexton SJ, Granieri MA, Lentz AC. Survey on the Contemporary Management of Intraoperative Urethral Injuries During Penile Prosthesis Implantation. J Sex Med 2018;15:576-581. Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Further explorations of the facing bias in biological motion perception: perspective cues, observer sex, and response times.

Directory of Open Access Journals (Sweden)

Ben Schouten

Full Text Available The human visual system has evolved to be highly sensitive to visual information about other persons and their movements as is illustrated by the effortless perception of point-light figures or 'biological motion'. When presented orthographically, a point-light walker is interpreted in two anatomically plausible ways: As 'facing the viewer' or as 'facing away' from the viewer. However, human observers show a 'facing bias': They perceive such a point-light walker as facing towards them in about 70-80% of the cases. In studies exploring the role of social and biological relevance as a possible account for the facing bias, we found a 'figure gender effect': Male point-light figures elicit a stronger facing bias than female point-light figures. Moreover, we also found an 'observer gender effect': The 'figure gender effect' was stronger for male than for female observers. In the present study we presented to 11 males and 11 females point-light walkers of which, very subtly, the perspective information was manipulated by modifying the earlier reported 'perspective technique'. Proportions of 'facing the viewer' responses and reaction times were recorded. Results show that human observers, even in the absence of local shape or size cues, easily pick up on perspective cues, confirming recent demonstrations of high visual sensitivity to cues on whether another person is potentially approaching. We also found a consistent difference in how male and female observers respond to stimulus variations (figure gender or perspective cues that cause variations in the perceived in-depth orientation of a point-light walker. Thus, the 'figure gender effect' is possibly caused by changes in the relative locations and motions of the dots that the perceptual system tends to interpret as perspective cues. Third, reaction time measures confirmed the existence of the facing bias and recent research showing faster detection of approaching than receding biological motion.

A retrieval-based approach to eliminating hindsight bias.

Science.gov (United States)

Van Boekel, Martin; Varma, Keisha; Varma, Sashank

2017-03-01

Individuals exhibit hindsight bias when they are unable to recall their original responses to novel questions after correct answers are provided to them. Prior studies have eliminated hindsight bias by modifying the conditions under which original judgments or correct answers are encoded. Here, we explored whether hindsight bias can be eliminated by manipulating the conditions that hold at retrieval. Our retrieval-based approach predicts that if the conditions at retrieval enable sufficient discrimination of memory representations of original judgments from memory representations of correct answers, then hindsight bias will be reduced or eliminated. Experiment 1 used the standard memory design to replicate the hindsight bias effect in middle-school students. Experiments 2 and 3 modified the retrieval phase of this design, instructing participants beforehand that they would be recalling both their original judgments and the correct answers. As predicted, this enabled participants to form compound retrieval cues that discriminated original judgment traces from correct answer traces, and eliminated hindsight bias. Experiment 4 found that when participants were not instructed beforehand that they would be making both recalls, they did not form discriminating retrieval cues, and hindsight bias returned. These experiments delineate the retrieval conditions that produce-and fail to produce-hindsight bias.

Response of six neutron survey meters in mixed fields of fast and thermal neutrons.

Science.gov (United States)

Kim, S I; Kim, B H; Chang, I; Lee, J I; Kim, J L; Pradhan, A S

2013-10-01

Calibration neutron fields have been developed at KAERI (Korea Atomic Energy Research Institute) to study the responses of commonly used neutron survey meters in the presence of fast neutrons of energy around 10 MeV. The neutron fields were produced by using neutrons from the (241)Am-Be sources held in a graphite pile and a DT neutron generator. The spectral details and the ambient dose equivalent rates of the calibration fields were established, and the responses of six neutron survey meters were evaluated. Four single-moderator-based survey meters exhibited an under-responses ranging from ∼9 to 55 %. DINEUTRUN, commonly used in fields around nuclear reactors, exhibited an over-response by a factor of three in the thermal neutron field and an under-response of ∼85 % in the mixed fields. REM-500 (tissue-equivalent proportional counter) exhibited a response close to 1.0 in the fast neutron fields and an under-response of ∼50 % in the thermal neutron field.

Attentional bias modification encourages healthy eating.

Science.gov (United States)

Kakoschke, Naomi; Kemps, Eva; Tiggemann, Marika

2014-01-01

The continual exposure to unhealthy food cues in the environment encourages poor dietary habits, in particular consuming too much fat and sugar, and not enough fruit and vegetables. According to Berridge's (2009) model of food reward, unhealthy eating is a behavioural response to biased attentional processing. The present study used an established attentional bias modification paradigm to discourage the consumption of unhealthy food and instead promote healthy eating. Participants were 146 undergraduate women who were randomly assigned to two groups: one was trained to direct their attention toward pictures of healthy food ('attend healthy' group) and the other toward unhealthy food ('attend unhealthy' group). It was found that participants trained to attend to healthy food cues demonstrated an increased attentional bias for such cues and ate relatively more of the healthy than unhealthy snacks compared to the 'attend unhealthy' group. Theoretically, the results support the postulated link between biased attentional processing and consumption (Berridge, 2009). At a practical level, they offer potential scope for interventions that focus on eating well. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Response Shift Bias in Self-Report Tests: A Function of an Expectation of Change or a Shift in Internal Scaling?

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Riedel, Sharon; And Others

Self-report, pre/post testing is a frequently employed measure of therapeutic change. To investigate whether expectation of change might be an alternative explanation to the scale shift explanation of response shift bias in a self-report measure, a two-session assertiveness training intervention for college women was evaluated under manipulated…

A hidden bias in a common calorimeter calibration scheme

International Nuclear Information System (INIS)

Lincoln, Don; Morrow, Greg; Kasper, Peter

1994-01-01

In this paper, a common calorimeter calibration scheme is explored and a hidden bias found. Since this bias mimics a non-linearity in response in the calorimeter, it must be understood and removed from the calibration before true non-linearities are investigated. The effect and its removal are explored and understood through straightforward calculus and algebra. ((orig.))

USING COSMIC MICROWAVE BACKGROUND LENSING TO CONSTRAIN THE MULTIPLICATIVE BIAS OF COSMIC SHEAR

International Nuclear Information System (INIS)

Vallinotto, Alberto

2012-01-01

Weak gravitational lensing is one of the key probes of cosmology. Cosmic shear surveys aimed at measuring the distribution of matter in the universe are currently being carried out (Pan-STARRS) or planned for the coming decade (DES, LSST, EUCLID, WFIRST). Crucial to the success of these surveys is the control of systematics. In this work, a new method to constrain one such family of systematics, known as multiplicative bias, is proposed. This method exploits the cross-correlation between weak-lensing measurements from galaxy surveys and the ones obtained from high-resolution cosmic microwave background experiments. This cross-correlation is shown to have the power to break the degeneracy between the normalization of the matter power spectrum and the multiplicative bias of cosmic shear and to be able to constrain the latter to a few percent.

Active and Adaptive Learning from Biased Data with Applications in Astronomy

DEFF Research Database (Denmark)

Kremer, Jan

This thesis addresses the problem of machine learning from biased datasets in the context of astronomical applications. In astronomy there are many cases in which the training sample does not follow the true distribution. The thesis examines different types of biases and proposes algorithms...... set. Against this background, the thesis begins with a survey of active learning algorithms for the support vector machine. If the cost of additional labeling is prohibitive, unlabeled data can often be utilized instead and the sample selection bias can be overcome through domain adaptation, that is...... to handle them. During learning and when applying the predictive model, active learning enables algorithms to select training examples from a pool of unlabeled data and to request the labels. This allows for selecting examples that maximize the algorithm's accuracy despite an initial bias in the training...

Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence.

Science.gov (United States)

Chaby, Lauren E; Cavigelli, Sonia A; White, Amanda; Wang, Kayllie; Braithwaite, Victoria A

2013-01-01

Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid "stress" hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision-making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g., isolation, crowding, cage tilt) were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias [F (1, 12) = 5.000, P chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object [T (1, 14) = 2.240, P = 0.04; T (1, 14) = 2.419, P = 0.03, respectively]. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions.

Technical evaluation of available state of Nevada survey instruments

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-02-01

Argonne National Laboratory (ANL) is reviewing the survey research studies completed by Mountain West Research (1987-1989) for the state of Nevada`s Nuclear Waste Project Office. In this research, 14 survey instruments were used to seek data on whether perceptions of risk could be associated with the possible siting of a high-level radioactive waste repository in Nevada and could be a dominant source of potential, significant, adverse economic impacts. This report presents results from phase 1 of the review, in which ANL contracted with the National Opinion Research Center (NORC) at the University of Chicago to evaluate the technical merits of the nine survey instruments that ANL had been able to acquire. The scope of NORC`s work was limited to rating the questions and stating their strengths and weaknesses. NORC concluded that the surveys could provide valuable data about risk perceptions and potential behavioral responses. NORC identified a few minor problems with a number of questions and the calculated response rates but claimed these problems would probably not have any major biasing effect. The NORC evaluation would have been more complete if the terms used in the questionnaires had been defined, all survey instruments had been acquired, and all data had been made available to the public.

Technical evaluation of available state of Nevada survey instruments

International Nuclear Information System (INIS)

1993-02-01

Argonne National Laboratory (ANL) is reviewing the survey research studies completed by Mountain West Research (1987-1989) for the state of Nevada's Nuclear Waste Project Office. In this research, 14 survey instruments were used to seek data on whether perceptions of risk could be associated with the possible siting of a high-level radioactive waste repository in Nevada and could be a dominant source of potential, significant, adverse economic impacts. This report presents results from phase 1 of the review, in which ANL contracted with the National Opinion Research Center (NORC) at the University of Chicago to evaluate the technical merits of the nine survey instruments that ANL had been able to acquire. The scope of NORC's work was limited to rating the questions and stating their strengths and weaknesses. NORC concluded that the surveys could provide valuable data about risk perceptions and potential behavioral responses. NORC identified a few minor problems with a number of questions and the calculated response rates but claimed these problems would probably not have any major biasing effect. The NORC evaluation would have been more complete if the terms used in the questionnaires had been defined, all survey instruments had been acquired, and all data had been made available to the public

Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence

Directory of Open Access Journals (Sweden)

Lauren eChaby

2013-07-01

Full Text Available Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid stress hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g. isolation, crowding, cage tilt were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias (F1,12 = 5.000, P < 0.05, altered coping response (T1,14 = 2.216, P = 0.04, and accelerated decision making (T1,14 = 3.245, P = 0.01. Exposure to chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object (T1,14 = 2.240, P = 0.04; T1,14 = 2.419, P = 0.03, respectively. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions. Stress during adolescence also induced short-term changes in the way animals moved around a novel environment.

Response bias in international marketing research

NARCIS (Netherlands)

de Jong, M.G.

2006-01-01

The saturation of domestic markets in the industrialized parts of the world, combined with increased competition in home markets from foreign competitors forces many companies to look for opportunities beyond their national boundaries. Surveys are a crucial source of data in international marketing

The effect of a medical opinion on self-perceptions of weight for Mexican adults: perception of change and cognitive biases.

Science.gov (United States)

Easton, Jonathan F; Stephens, Christopher R; Román Sicilia, Heriberto

2017-01-01

This study analysed the relationship between perceived and actual Body Mass Index (BMI) and the effect of a prior identification of obesity by a medical professional for adults using difference in response for two distinct BMI self-perception questions. Typically, self-perception studies only investigate the relation with current weight, whereas here the focus is on the self-perception of weight differences. A statistical approach was used to assess responses to the Mexican ENSANUT 2006 survey. Adults in the range of BMI from 13 to 60 were tested on responses to a categorical question and a figure rating scale self-perception question. Differences in response by gender and identification of obesity by a medical professional were analysed using linear regression. Results indicated that regardless of current BMI and gender, a verbal intervention by a medical professional will increase perceived BMI independently of actual BMI but does not necessarily make the identified obese more accurate in their BMI estimates. A shift in the average self-perception was seen with a higher response for the identified obese. A linear increase in perceived BMI as a function of actual BMI was observed in the range BMI self-image, to be considerably less. It was seen that an identification of obesity by a health care professional did not improve ability to judge weight but, rather, served as a new anchor from which the identified obese judge their weight, suggesting that even those identified obese who have lost weight, perceive their weight to be greater than it actually is. We believe that these results can be explained in terms of two cognitive biases; the self-serving bias and the anchoring bias.

Both bias and lack of knowledge influence organizational focus on first case of the day starts.

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Dexter, Elisabeth U; Dexter, Franklin; Masursky, Danielle; Garver, Michael P; Nussmeier, Nancy A

2009-04-01

The economic costs of reducing first case delays are often high, because efforts need to be applied to multiple operating rooms (ORs) simultaneously. Nevertheless, delays in starting first cases of the day are a common topic in OR committee meetings. We added three scientific questions to a 24 question online, anonymous survey performed before the implementation of a new OR information system. The 57 respondents cared sufficiently about OR management at the United States teaching hospital to complete all questions. The survey revealed reasons why personnel may focus on the small reductions in nonoperative time achievable by reducing tardiness in first cases of the day. (A) Respondents lacked knowledge about principles in reducing over-utilized OR time to increase OR efficiency, based on their answering the relevant question correctly at a rate no different from guessing at random. Those results differed from prior findings of responses at a rate worse than random, resulting from a bias on the day of surgery of making decisions that increase clinical work per unit time. (B) Most respondents falsely believed that a 10 min delay at the start of the day causes subsequent cases to start at least 10 min late (P less time than scheduled (P = 0.008 versus chance). No one who demonstrated knowledge (C) about cases sometimes taking less time than scheduled applied that information to their response to (B) regarding cases starting late (P = 0.0002). Knowledge of OR efficiency was low among the respondents working in ORs. Nevertheless, the apparent absence of bias shows that education may influence behavior. In contrast, presence of bias on matters of tardiness of start times shows that education may be of no benefit. As the latter results match findings of previous studies of scheduling decisions, interventions to reduce patient and surgeon waiting from start times may depend principally on the application of automation to guide decision-making.

Survey of Expert Opinion on Intelligence: Causes of International Differences in Cognitive Ability Tests.

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Rindermann, Heiner; Becker, David; Coyle, Thomas R

2016-01-01

Following Snyderman and Rothman (1987, 1988), we surveyed expert opinions on the current state of intelligence research. This report examines expert opinions on causes of international differences in student assessment and psychometric IQ test results. Experts were surveyed about the importance of culture, genes, education (quantity and quality), wealth, health, geography, climate, politics, modernization, sampling error, test knowledge, discrimination, test bias, and migration. The importance of these factors was evaluated for diverse countries, regions, and groups including Finland, East Asia, sub-Saharan Africa, Southern Europe, the Arabian-Muslim world, Latin America, Israel, Jews in the West, Roma (gypsies), and Muslim immigrants. Education was rated by N = 71 experts as the most important cause of international ability differences. Genes were rated as the second most relevant factor but also had the highest variability in ratings. Culture, health, wealth, modernization, and politics were the next most important factors, whereas other factors such as geography, climate, test bias, and sampling error were less important. The paper concludes with a discussion of limitations of the survey (e.g., response rates and validity of expert opinions).

Changes in cue reactivity and attentional bias following experimental cue exposure and response prevention: a laboratory study of the effects of D-cycloserine in heavy drinkers.

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Kamboj, Sunjeev K; Massey-Chase, Rachel; Rodney, Lydia; Das, Ravi; Almahdi, Basil; Curran, H Valerie; Morgan, Celia J A

2011-09-01

The effects of D-cycloserine (DCS) in animal models of anxiety disorders and addiction indicate a role for N-methyl D-aspartate (NMDA) receptors in extinction learning. Exposure/response prevention treatments for anxiety disorders in humans are enhanced by DCS, suggesting a promising co-therapy regime, mediated by NMDA receptors. Exposure/response prevention may also be effective in problematic drinkers, and DCS might enhance habituation to cues in these individuals. Since heavy drinkers show ostensible conditioned responses to alcohol cues, habituation following exposure/response prevention should be evident in these drinkers, with DCS enhancing this effect. The objective of this study is to investigate the effect of DCS on exposure/response prevention in heavy drinkers. In a randomised, double-blind, placebo-controlled study, heavy social drinkers recruited from the community received either DCS (125 mg; n = 19) or placebo (n = 17) 1 h prior to each of two sessions of exposure/response prevention. Cue reactivity and attentional bias were assessed during these two sessions and at a third follow-up session. Between-session drinking behaviour was recorded. Robust cue reactivity and attentional bias to alcohol cues was evident, as expected of heavy drinkers. Within- and between-session habituation of cue reactivity, as well as a reduction in attentional bias to alcohol cues over time was found. However, there was no evidence of greater habituation in the DCS group. Subtle stimulant effects (increased subjective contentedness and euphoria) which were unrelated to exposure/response prevention were found following DCS. DCS does not appear to enhance habituation of alcohol cue reactivity in heavy non-dependent drinkers. Its utility in enhancing treatments based on exposure/response prevention in dependent drinkers or drug users remains open.

Revisiting the "Art Bias" in Lay Conceptions of Creativity

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Glaveanu, Vlad Petre

2014-01-01

This article explores the "art bias"--the pervasive association between creativity and art in implicit theories of creativity. It also attempts to connect creativity research in this area with literature on the theory of social representations. The data comes from an online survey completed by 195 participants mainly from the United…

Rising Mercury, Rising Hostility: How Heat Affects Survey Response

Science.gov (United States)

Cohen, Alexander H.; Krueger, James S.

2016-01-01

Recent social scientific research has examined connections between public opinion and weather conditions. This article contributes to this literature by analyzing the relationship between high temperature and survey response. Because hot temperatures are associated with aggression, irritation, and negativity, such conditions should lead to the…

Validity testing and neuropsychology practice in the VA healthcare system: results from recent practitioner survey (.).

Science.gov (United States)

Young, J Christopher; Roper, Brad L; Arentsen, Timothy J

2016-05-01

A survey of neuropsychologists in the Veterans Health Administration examined symptom/performance validity test (SPVT) practices and estimated base rates for patient response bias. Invitations were emailed to 387 psychologists employed within the Veterans Affairs (VA), identified as likely practicing neuropsychologists, resulting in 172 respondents (44.4% response rate). Practice areas varied, with 72% at least partially practicing in general neuropsychology clinics and 43% conducting VA disability exams. Mean estimated failure rates were 23.0% for clinical outpatient, 12.9% for inpatient, and 39.4% for disability exams. Failure rates were the highest for mTBI and PTSD referrals. Failure rates were positively correlated with the number of cases seen and frequency and number of SPVT use. Respondents disagreed regarding whether one (45%) or two (47%) failures are required to establish patient response bias, with those administering more measures employing the more stringent criterion. Frequency of the use of specific SPVTs is reported. Base rate estimates for SPVT failure in VA disability exams are comparable to those in other medicolegal settings. However, failure in routine clinical exams is much higher in the VA than in other settings, possibly reflecting the hybrid nature of the VA's role in both healthcare and disability determination. Generally speaking, VA neuropsychologists use SPVTs frequently and eschew pejorative terms to describe their failure. Practitioners who require only one SPVT failure to establish response bias may overclassify patients. Those who use few or no SPVTs may fail to identify response bias. Additional clinical and theoretical implications are discussed.

Ingroup-outgroup bias in contagious yawning by chimpanzees supports link to empathy.

Directory of Open Access Journals (Sweden)

Matthew W Campbell

2011-04-01

Full Text Available Humans favor others seen as similar to themselves (ingroup over people seen as different (outgroup, even without explicitly stated bias. Ingroup-outgroup bias extends to involuntary responses, such as empathy for pain. However, empathy biases have not been tested in our close primate relatives. Contagious yawning has been theoretically and empirically linked to empathy. If empathy underlies contagious yawning, we predict that subjects should show an ingroup-outgroup bias by yawning more in response to watching ingroup members yawn than outgroup. Twenty-three chimpanzees (Pan troglodytes from two separate groups watched videos of familiar and unfamiliar individuals yawning or at rest (control. The chimpanzees yawned more when watching the familiar yawns than the familiar control or the unfamiliar yawns, demonstrating an ingroup-outgroup bias in contagious yawning. These results provide further empirical support that contagious yawning is a measure of empathy, which may be useful for evolutionary biology and mental health.

A Neural Marker for Social Bias Toward In-group Accents.

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Bestelmeyer, Patricia E G; Belin, Pascal; Ladd, D Robert

2015-10-01

Accents provide information about the speaker's geographical, socio-economic, and ethnic background. Research in applied psychology and sociolinguistics suggests that we generally prefer our own accent to other varieties of our native language and attribute more positive traits to it. Despite the widespread influence of accents on social interactions, educational and work settings the neural underpinnings of this social bias toward our own accent and, what may drive this bias, are unexplored. We measured brain activity while participants from two different geographical backgrounds listened passively to 3 English accent types embedded in an adaptation design. Cerebral activity in several regions, including bilateral amygdalae, revealed a significant interaction between the participants' own accent and the accent they listened to: while repetition of own accents elicited an enhanced neural response, repetition of the other group's accent resulted in reduced responses classically associated with adaptation. Our findings suggest that increased social relevance of, or greater emotional sensitivity to in-group accents, may underlie the own-accent bias. Our results provide a neural marker for the bias associated with accents, and show, for the first time, that the neural response to speech is partly shaped by the geographical background of the listener. © The Author 2014. Published by Oxford University Press.

Unawareness of Self-interest Bias in Moral Judgments of Others’ Behavior

Directory of Open Access Journals (Sweden)

Bocian Konrad

2014-12-01

Full Text Available Previous studies (Bocian & Wojciszke, 2014 showed that self-interest biases moral perception of others’ unethical actions. Moreover, affective changes in attitudinal responses towards the perpetrator of an immoral act drives the bias. In the present studies, we attempted to answer the question whether people are aware of the self-interest bias in their judgments of others’ behavior. We conducted two experiments showing that moral judgments of verbally described and imagined actions were dominated by norms rather than self-interest (Study 1 and that people were not aware that self-interest distorted their moral judgment (Study 2. The unawareness of the self-interest bias among the participants was attributable to omission of their own emotional responses when forecasting their moral judgments. We discuss the importance of emotions presence in studies on moral judgments as well as contribution of the present research to the intuitionist approach to moral judgment.

Medical School Factors Associated with Changes in Implicit and Explicit Bias Against Gay and Lesbian People among 3492 Graduating Medical Students.

Science.gov (United States)

Phelan, Sean M; Burke, Sara E; Hardeman, Rachel R; White, Richard O; Przedworski, Julia; Dovidio, John F; Perry, Sylvia P; Plankey, Michael; A Cunningham, Brooke; Finstad, Deborah; W Yeazel, Mark; van Ryn, Michelle

2017-11-01

Implicit and explicit bias among providers can influence the quality of healthcare. Efforts to address sexual orientation bias in new physicians are hampered by a lack of knowledge of school factors that influence bias among students. To determine whether medical school curriculum, role modeling, diversity climate, and contact with sexual minorities predict bias among graduating students against gay and lesbian people. Prospective cohort study. A sample of 4732 first-year medical students was recruited from a stratified random sample of 49 US medical schools in the fall of 2010 (81% response; 55% of eligible), of which 94.5% (4473) identified as heterosexual. Seventy-eight percent of baseline respondents (3492) completed a follow-up survey in their final semester (spring 2014). Medical school predictors included formal curriculum, role modeling, diversity climate, and contact with sexual minorities. Outcomes were year 4 implicit and explicit bias against gay men and lesbian women, adjusted for bias at year 1. In multivariate models, lower explicit bias against gay men and lesbian women was associated with more favorable contact with LGBT faculty, residents, students, and patients, and perceived skill and preparedness for providing care to LGBT patients. Greater explicit bias against lesbian women was associated with discrimination reported by sexual minority students (b = 1.43 [0.16, 2.71]; p = 0.03). Lower implicit sexual orientation bias was associated with more frequent contact with LGBT faculty, residents, students, and patients (b = -0.04 [-0.07, -0.01); p = 0.008). Greater implicit bias was associated with more faculty role modeling of discriminatory behavior (b = 0.34 [0.11, 0.57); p = 0.004). Medical schools may reduce bias against sexual minority patients by reducing negative role modeling, improving the diversity climate, and improving student preparedness to care for this population.

Sympathetic bias.

Science.gov (United States)

Levy, David M; Peart, Sandra J

2008-06-01

We wish to deal with investigator bias in a statistical context. We sketch how a textbook solution to the problem of "outliers" which avoids one sort of investigator bias, creates the temptation for another sort. We write down a model of the approbation seeking statistician who is tempted by sympathy for client to violate the disciplinary standards. We give a simple account of one context in which we might expect investigator bias to flourish. Finally, we offer tentative suggestions to deal with the problem of investigator bias which follow from our account. As we have given a very sparse and stylized account of investigator bias, we ask what might be done to overcome this limitation.

Bias modification training can alter approach bias and chocolate consumption.

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Schumacher, Sophie E; Kemps, Eva; Tiggemann, Marika

2016-01-01

Recent evidence has demonstrated that bias modification training has potential to reduce cognitive biases for attractive targets and affect health behaviours. The present study investigated whether cognitive bias modification training could be applied to reduce approach bias for chocolate and affect subsequent chocolate consumption. A sample of 120 women (18-27 years) were randomly assigned to an approach-chocolate condition or avoid-chocolate condition, in which they were trained to approach or avoid pictorial chocolate stimuli, respectively. Training had the predicted effect on approach bias, such that participants trained to approach chocolate demonstrated an increased approach bias to chocolate stimuli whereas participants trained to avoid such stimuli showed a reduced bias. Further, participants trained to avoid chocolate ate significantly less of a chocolate muffin in a subsequent taste test than participants trained to approach chocolate. Theoretically, results provide support for the dual process model's conceptualisation of consumption as being driven by implicit processes such as approach bias. In practice, approach bias modification may be a useful component of interventions designed to curb the consumption of unhealthy foods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Forward-biased nanophotonic detector for ultralow-energy dissipation receiver

Science.gov (United States)

Nozaki, Kengo; Matsuo, Shinji; Fujii, Takuro; Takeda, Koji; Shinya, Akihiko; Kuramochi, Eiichi; Notomi, Masaya

2018-04-01

Generally, reverse-biased photodetectors (PDs) are used for high-speed optical receivers. The forward voltage region is only utilized in solar-cells, and this photovoltaic operation would not be concurrently obtained with high efficiency and high speed operation. Here we report that photonic-crystal waveguide PDs enable forward-biased high-speed operation at 40 Gbit/s with keeping high responsivity (0.88 A/W). Within our knowledge, this is the first demonstration of the forward-biased PDs with high responsivity. This achievement is attributed to the ultracompactness of our PD and the strong light confinement within the absorber and depleted regions, thereby enabling efficient photo-carrier generation and fast extraction. This result indicates that it is possible to construct a high-speed and ultracompact photo-receiver without an electrical amplifier nor an external bias circuit. Since there is no electrical energy required, our estimation shows that the consumption energy is just the optical energy of the injected signal pulse which is about 1 fJ/bit. Hence, it will lead to an ultimately efficient and highly integrable optical-to-electrical converter in a chip, which will be a key ingredient for dense nanophotonic communication and processors.

Forward-biased nanophotonic detector for ultralow-energy dissipation receiver

Directory of Open Access Journals (Sweden)

Kengo Nozaki

2018-04-01

Full Text Available Generally, reverse-biased photodetectors (PDs are used for high-speed optical receivers. The forward voltage region is only utilized in solar-cells, and this photovoltaic operation would not be concurrently obtained with high efficiency and high speed operation. Here we report that photonic-crystal waveguide PDs enable forward-biased high-speed operation at 40 Gbit/s with keeping high responsivity (0.88 A/W. Within our knowledge, this is the first demonstration of the forward-biased PDs with high responsivity. This achievement is attributed to the ultracompactness of our PD and the strong light confinement within the absorber and depleted regions, thereby enabling efficient photo-carrier generation and fast extraction. This result indicates that it is possible to construct a high-speed and ultracompact photo-receiver without an electrical amplifier nor an external bias circuit. Since there is no electrical energy required, our estimation shows that the consumption energy is just the optical energy of the injected signal pulse which is about 1 fJ/bit. Hence, it will lead to an ultimately efficient and highly integrable optical-to-electrical converter in a chip, which will be a key ingredient for dense nanophotonic communication and processors.

Biases in Visual, Auditory, and Audiovisual Perception of Space

Science.gov (United States)

Odegaard, Brian; Wozny, David R.; Shams, Ladan

2015-01-01

Localization of objects and events in the environment is critical for survival, as many perceptual and motor tasks rely on estimation of spatial location. Therefore, it seems reasonable to assume that spatial localizations should generally be accurate. Curiously, some previous studies have reported biases in visual and auditory localizations, but these studies have used small sample sizes and the results have been mixed. Therefore, it is not clear (1) if the reported biases in localization responses are real (or due to outliers, sampling bias, or other factors), and (2) whether these putative biases reflect a bias in sensory representations of space or a priori expectations (which may be due to the experimental setup, instructions, or distribution of stimuli). Here, to address these questions, a dataset of unprecedented size (obtained from 384 observers) was analyzed to examine presence, direction, and magnitude of sensory biases, and quantitative computational modeling was used to probe the underlying mechanism(s) driving these effects. Data revealed that, on average, observers were biased towards the center when localizing visual stimuli, and biased towards the periphery when localizing auditory stimuli. Moreover, quantitative analysis using a Bayesian Causal Inference framework suggests that while pre-existing spatial biases for central locations exert some influence, biases in the sensory representations of both visual and auditory space are necessary to fully explain the behavioral data. How are these opposing visual and auditory biases reconciled in conditions in which both auditory and visual stimuli are produced by a single event? Potentially, the bias in one modality could dominate, or the biases could interact/cancel out. The data revealed that when integration occurred in these conditions, the visual bias dominated, but the magnitude of this bias was reduced compared to unisensory conditions. Therefore, multisensory integration not only improves the

Biases in Visual, Auditory, and Audiovisual Perception of Space.

Directory of Open Access Journals (Sweden)

Brian Odegaard

2015-12-01

Full Text Available Localization of objects and events in the environment is critical for survival, as many perceptual and motor tasks rely on estimation of spatial location. Therefore, it seems reasonable to assume that spatial localizations should generally be accurate. Curiously, some previous studies have reported biases in visual and auditory localizations, but these studies have used small sample sizes and the results have been mixed. Therefore, it is not clear (1 if the reported biases in localization responses are real (or due to outliers, sampling bias, or other factors, and (2 whether these putative biases reflect a bias in sensory representations of space or a priori expectations (which may be due to the experimental setup, instructions, or distribution of stimuli. Here, to address these questions, a dataset of unprecedented size (obtained from 384 observers was analyzed to examine presence, direction, and magnitude of sensory biases, and quantitative computational modeling was used to probe the underlying mechanism(s driving these effects. Data revealed that, on average, observers were biased towards the center when localizing visual stimuli, and biased towards the periphery when localizing auditory stimuli. Moreover, quantitative analysis using a Bayesian Causal Inference framework suggests that while pre-existing spatial biases for central locations exert some influence, biases in the sensory representations of both visual and auditory space are necessary to fully explain the behavioral data. How are these opposing visual and auditory biases reconciled in conditions in which both auditory and visual stimuli are produced by a single event? Potentially, the bias in one modality could dominate, or the biases could interact/cancel out. The data revealed that when integration occurred in these conditions, the visual bias dominated, but the magnitude of this bias was reduced compared to unisensory conditions. Therefore, multisensory integration not only

Evaluation of non-response bias in mental health determinants and outcomes in a large sample of pre-adolescents

NARCIS (Netherlands)

de Winter, AF; Oldehinkel, AJ; Veenstra, René; Brunnekreef, JA; Verhulst, FC; Ormel, J

2005-01-01

Since non- response may jeopardize the validity of studies, comprehensive assessment of non-response is a prerequisite for proper interpretation of study findings. Recently, the baseline assessment of the TRacking Adolescents' Individual Lives Survey ( TRAILS), a prospective cohort study among Dutch

Estimation of Sensitive Proportion by Randomized Response Data in Successive Sampling

Directory of Open Access Journals (Sweden)

Bo Yu

2015-01-01

Full Text Available This paper considers the problem of estimation for binomial proportions of sensitive or stigmatizing attributes in the population of interest. Randomized response techniques are suggested for protecting the privacy of respondents and reducing the response bias while eliciting information on sensitive attributes. In many sensitive question surveys, the same population is often sampled repeatedly on each occasion. In this paper, we apply successive sampling scheme to improve the estimation of the sensitive proportion on current occasion.

The nature of assembly bias - III. Observational properties

Science.gov (United States)

Lacerna, Ivan; Padilla, Nelson; Stasyszyn, Federico

2014-10-01

We analyse galaxies in groups in the Sloan Digital Sky Survey (SDSS) and find a weak but significant assembly-type bias, where old central galaxies have a higher clustering amplitude (61 ± 9 per cent) at scales >1 h-1 Mpc than young central galaxies of equal host halo mass (Mh ˜ 1011.8 h- 1 M⊙). The observational sample is volume limited out to z = 0.1 with Mr - 5 log (h) ≤ -19.6. We construct a mock catalogue of galaxies that shows a similar signal of assembly bias (46 ± 9 per cent) at the same halo mass. We then adapt the model presented by Lacerna & Padilla (Paper I) to redefine the overdensity peak height, which traces the assembly bias such that galaxies in equal density peaks show the same clustering regardless of their stellar age, but this time using observational features such as a flux limit. The proxy for peak height, which is proposed as a better alternative than the virial mass, consists in the total mass given by the mass of neighbour host haloes in cylinders centred at each central galaxy. The radius of the cylinder is parameterized as a function of stellar age and virial mass. The best-fitting sets of parameters that make the assembly bias signal lower than 5-15 per cent for both SDSS and mock central galaxies are similar. The idea behind the parameterization is not to minimize the bias, but it is to use this method to understand the physical features that produce the assembly bias effect. Even though the tracers of the density field used here differ significantly from those used in Paper I, our analysis of the simulated catalogue indicates that the different tracers produce correlated proxies, and therefore the reason behind assembly bias is the crowding of peaks in both simulations and the SDSS.

The Effects of Two Types of Appeal on Survey Response Rates.

Science.gov (United States)

Green, Kathy E.; And Others

The effects of two cover letter manipulations and their interactions with demographic variables on response to the initial mailing of a survey were investigated. The two manipulations, type of appeal and type of respondent group identification, were intended to affect respondents' perceptions of their social responsibility and position. In all,…

Students' gender bias in teaching evaluations

OpenAIRE

Punyanunt-Carter, Narissra; Carter, Stacy L.

2015-01-01

The goal of this study was to investigate if there is gender bias in student evaluations. Researchers administered a modified version of the teacher evaluation forms to 58 students (male=30; female=28) in a basic introductory communications class. Half the class was instructed to fill out the survey about a male professor, and the other half a female professor. Researchers broke down the evaluation results question by question in order to give a detailed account of the findings. Results revea...

A questionnaire survey of senior house officers/registrars response ...

African Journals Online (AJOL)

A questionnaire survey of senior house officers/registrars response to their training at University College Hospital, Ibadan. ... A regular conduct of auditing of training programmes is recommended. Keywords: Questionnaire ... spécialistes. Nous proposons l'organisation régulière de la verification de programme de formation.

Combination of biased forecasts: Bias correction or bias based weights?

OpenAIRE

Wenzel, Thomas

1999-01-01

Most of the literature on combination of forecasts deals with the assumption of unbiased individual forecasts. Here, we consider the case of biased forecasts and discuss two different combination techniques resulting in an unbiased forecast. On the one hand we correct the individual forecasts, and on the other we calculate bias based weights. A simulation study gives some insight in the situations where we should use the different methods.

Telephone versus face-to-face interviewing for household drug use surveys.

Science.gov (United States)

Aquilino, W S

1992-01-01

This research investigated the use of telephone versus face-to-face interviewing to gather data on the use of tobacco, alcohol, and illicit drugs. Telephone and personal drug use surveys of the 18-34 year-old household population were conducted in the state of New Jersey in 1986-1987. Survey modes were compared in terms of unit and item nonresponse rates, sample coverage, and levels of self-reported drug use. Results showed that the telephone survey achieved response rates lower than the personal survey, but comparable to telephone surveys of less threatening topics. Item nonresponse to sensitive drug questions was lower by phone than with the self-administered answer sheets in the personal mode. The exclusion of households without telephones in the telephone survey is a potential source of bias, and may lead to underestimation of alcohol and drug use for minority populations. After controlling for telephone status, the telephone survey furnished significantly lower drug use estimates on several indicators than the personal survey, with the largest mode differences found for Blacks.

Estimation bias and bias correction in reduced rank autoregressions

DEFF Research Database (Denmark)

Nielsen, Heino Bohn

2017-01-01

This paper characterizes the finite-sample bias of the maximum likelihood estimator (MLE) in a reduced rank vector autoregression and suggests two simulation-based bias corrections. One is a simple bootstrap implementation that approximates the bias at the MLE. The other is an iterative root...

Empathy costs: Negative emotional bias in high empathisers.

Science.gov (United States)

Chikovani, George; Babuadze, Lasha; Iashvili, Nino; Gvalia, Tamar; Surguladze, Simon

2015-09-30

Excessive empathy has been associated with compassion fatigue in health professionals and caregivers. We investigated an effect of empathy on emotion processing in 137 healthy individuals of both sexes. We tested a hypothesis that high empathy may underlie increased sensitivity to negative emotion recognition which may interact with gender. Facial emotion stimuli comprised happy, angry, fearful, and sad faces presented at different intensities (mild and prototypical) and different durations (500ms and 2000ms). The parameters of emotion processing were represented by discrimination accuracy, response bias and reaction time. We found that higher empathy was associated with better recognition of all emotions. We also demonstrated that higher empathy was associated with response bias towards sad and fearful faces. The reaction time analysis revealed that higher empathy in females was associated with faster (compared with males) recognition of mildly sad faces of brief duration. We conclude that although empathic abilities were providing for advantages in recognition of all facial emotional expressions, the bias towards emotional negativity may potentially carry a risk for empathic distress. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

FILTER-INDUCED BIAS IN Lyα EMITTER SURVEYS: A COMPARISON BETWEEN STANDARD AND TUNABLE FILTERS. GRAN TELESCOPIO CANARIAS PRELIMINARY RESULTS

Energy Technology Data Exchange (ETDEWEB)

De Diego, J. A.; De Leo, M. A. [Instituto de Astronomía, Universidad Nacional Autónoma de México Avenida Universidad 3000, Ciudad Universitaria, C.P. 04510, Distrito Federal (Mexico); Cepa, J.; Bongiovanni, A. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Verdugo, T. [Centro de Investigaciones de Astronomía (CIDA), Apartado Postal 264, Mérida 5101-A (Venezuela, Bolivarian Republic of); Sánchez-Portal, M. [Herschel Science Centre (HSC), European Space Agency Centre (ESAC)/INSA, Villanueva de la Cañada, Madrid (Spain); González-Serrano, J. I., E-mail: jdo@astro.unam.mx [Instituto de Física de Cantabria (CSIC-Universidad de Cantabria), E-39005 Santander (Spain)

2013-10-01

Lyα emitter (LAE) surveys have successfully used the excess in a narrowband filter compared to a nearby broadband image to find candidates. However, the odd spectral energy distribution (SED) of LAEs combined with the instrumental profile has important effects on the properties of the candidate samples extracted from these surveys. We investigate the effect of the bandpass width and the transmission profile of the narrowband filters used for extracting LAE candidates at redshifts z ≅ 6.5 through Monte Carlo simulations, and we present pilot observations to test the performance of tunable filters to find LAEs and other emission-line candidates. We compare the samples obtained using a narrow ideal rectangular filter, the Subaru NB921 narrowband filter, and sweeping across a wavelength range using the ultra-narrow-band tunable filters of the instrument OSIRIS, installed at the 10.4 m Gran Telescopio Canarias. We use this instrument for extracting LAE candidates from a small set of real observations. Broadband data from the Subaru, Hubble Space Telescope, and Spitzer databases were used for fitting SEDs to calculate photometric redshifts and to identify interlopers. Narrowband surveys are very efficient in finding LAEs in large sky areas, but the samples obtained are not evenly distributed in redshift along the filter bandpass, and the number of LAEs with equivalent widths <60 Å can be underestimated. These biased results do not appear in samples obtained using ultra-narrow-band tunable filters. However, the field size of tunable filters is restricted because of the variation of the effective wavelength across the image. Thus, narrowband and ultra-narrow-band surveys are complementary strategies to investigate high-redshift LAEs.

FILTER-INDUCED BIAS IN Lyα EMITTER SURVEYS: A COMPARISON BETWEEN STANDARD AND TUNABLE FILTERS. GRAN TELESCOPIO CANARIAS PRELIMINARY RESULTS

International Nuclear Information System (INIS)

De Diego, J. A.; De Leo, M. A.; Cepa, J.; Bongiovanni, A.; Verdugo, T.; Sánchez-Portal, M.; González-Serrano, J. I.

2013-01-01

Lyα emitter (LAE) surveys have successfully used the excess in a narrowband filter compared to a nearby broadband image to find candidates. However, the odd spectral energy distribution (SED) of LAEs combined with the instrumental profile has important effects on the properties of the candidate samples extracted from these surveys. We investigate the effect of the bandpass width and the transmission profile of the narrowband filters used for extracting LAE candidates at redshifts z ≅ 6.5 through Monte Carlo simulations, and we present pilot observations to test the performance of tunable filters to find LAEs and other emission-line candidates. We compare the samples obtained using a narrow ideal rectangular filter, the Subaru NB921 narrowband filter, and sweeping across a wavelength range using the ultra-narrow-band tunable filters of the instrument OSIRIS, installed at the 10.4 m Gran Telescopio Canarias. We use this instrument for extracting LAE candidates from a small set of real observations. Broadband data from the Subaru, Hubble Space Telescope, and Spitzer databases were used for fitting SEDs to calculate photometric redshifts and to identify interlopers. Narrowband surveys are very efficient in finding LAEs in large sky areas, but the samples obtained are not evenly distributed in redshift along the filter bandpass, and the number of LAEs with equivalent widths <60 Å can be underestimated. These biased results do not appear in samples obtained using ultra-narrow-band tunable filters. However, the field size of tunable filters is restricted because of the variation of the effective wavelength across the image. Thus, narrowband and ultra-narrow-band surveys are complementary strategies to investigate high-redshift LAEs

Biases in the OSSOS Detection of Large Semimajor Axis Trans-Neptunian Objects

Science.gov (United States)

Gladman, Brett; Shankman, Cory; OSSOS Collaboration

2017-10-01

The accumulating but small set of large semimajor axis trans-Neptunian objects (TNOs) shows an apparent clustering in the orientations of their orbits. This clustering must either be representative of the intrinsic distribution of these TNOs, or else have arisen as a result of observation biases and/or statistically expected variations for such a small set of detected objects. The clustered TNOs were detected across different and independent surveys, which has led to claims that the detections are therefore free of observational bias. This apparent clustering has led to the so-called “Planet 9” hypothesis that a super-Earth currently resides in the distant solar system and causes this clustering. The Outer Solar System Origins Survey (OSSOS) is a large program that ran on the Canada-France-Hawaii Telescope from 2013 to 2017, discovering more than 800 new TNOs. One of the primary design goals of OSSOS was the careful determination of observational biases that would manifest within the detected sample. We demonstrate the striking and non-intuitive biases that exist for the detection of TNOs with large semimajor axes. The eight large semimajor axis OSSOS detections are an independent data set, of comparable size to the conglomerate samples used in previous studies. We conclude that the orbital distribution of the OSSOS sample is consistent with being detected from a uniform underlying angular distribution.

Researchers' Perceptions of Statistical Significance Contribute to Bias in Health and Exercise Science

Science.gov (United States)

Buchanan, Taylor L.; Lohse, Keith R.

2016-01-01

We surveyed researchers in the health and exercise sciences to explore different areas and magnitudes of bias in researchers' decision making. Participants were presented with scenarios (testing a central hypothesis with p = 0.06 or p = 0.04) in a random order and surveyed about what they would do in each scenario. Participants showed significant…

Detection probability in aerial surveys of feral horses

Science.gov (United States)

Ransom, Jason I.

2011-01-01

Observation bias pervades data collected during aerial surveys of large animals, and although some sources can be mitigated with informed planning, others must be addressed using valid sampling techniques that carefully model detection probability. Nonetheless, aerial surveys are frequently employed to count large mammals without applying such methods to account for heterogeneity in visibility of animal groups on the landscape. This often leaves managers and interest groups at odds over decisions that are not adequately informed. I analyzed detection of feral horse (Equus caballus) groups by dual independent observers from 24 fixed-wing and 16 helicopter flights using mixed-effect logistic regression models to investigate potential sources of observation bias. I accounted for observer skill, population location, and aircraft type in the model structure and analyzed the effects of group size, sun effect (position related to observer), vegetation type, topography, cloud cover, percent snow cover, and observer fatigue on detection of horse groups. The most important model-averaged effects for both fixed-wing and helicopter surveys included group size (fixed-wing: odds ratio = 0.891, 95% CI = 0.850–0.935; helicopter: odds ratio = 0.640, 95% CI = 0.587–0.698) and sun effect (fixed-wing: odds ratio = 0.632, 95% CI = 0.350–1.141; helicopter: odds ratio = 0.194, 95% CI = 0.080–0.470). Observer fatigue was also an important effect in the best model for helicopter surveys, with detection probability declining after 3 hr of survey time (odds ratio = 0.278, 95% CI = 0.144–0.537). Biases arising from sun effect and observer fatigue can be mitigated by pre-flight survey design. Other sources of bias, such as those arising from group size, topography, and vegetation can only be addressed by employing valid sampling techniques such as double sampling, mark–resight (batch-marked animals), mark–recapture (uniquely marked and

Spatial uncertainty in bias corrected climate change projections and hydrogeological impacts

DEFF Research Database (Denmark)

Seaby, Lauren Paige; Refsgaard, Jens Christian; Sonnenborg, Torben

2015-01-01

Model pairing, this paper analyses the relationship between complexity and robustness of three distribution-based scaling (DBS) bias correction methods applied to daily precipitation at various spatial scales. Hydrological simulations are forced by CM inputs to assess the spatial uncertainty......The question of which climate model bias correction methods and spatial scales for correction are optimal for both projecting future hydrological changes as well as removing initial model bias has so far received little attention. For 11 climate models (CMs), or GCM/RCM – Global/Regional Climate...... signals. The magnitude of spatial bias seen in precipitation inputs does not necessarily correspond to the magnitude of biases seen in hydrological outputs. Variables that integrate basin responses over time and space are more sensitive to mean spatial biases and less so on extremes. Hydrological...

Weight bias in work settings - a qualitative review.

Science.gov (United States)

Giel, Katrin Elisabeth; Thiel, Ansgar; Teufel, Martin; Mayer, Jochen; Zipfel, Stephan

2010-02-01

Studies have repeatedly demonstrated the influence of physical appearance on behavior and treatment of individuals in work settings. A high proportion of obese individuals in the USA have reported perceived discrimination in the work place due to their body weight. The present review examines the specific kind, context and extent of a weight bias in work settings. We performed a literature search in the scientific databases PubMed and PsychINFO to identify studies which have investigated aspects of a potential weight bias in the occupational context. There is evidence from self-report data, surveys, and laboratory research for a weight bias in five aspects of work life. Evidence shows that obesity is a general barrier to employment, certain professions and professional success. Obese individuals are at higher risk of encountering stereotypes concerning their work-related qualities and for general unequal treatment in the work place. Current evidence reveals a weight bias in several areas in the work place. The ecological validity of results is limited due to the predominant reliance on laboratory studies with student samples. Field studies are needed to examine weight-based discrimination in actual work environments as well as to uncover underlying mechanisms. Copyright 2010 S. Karger AG, Basel.

Influence of encoding instructions and response bias on cross-cultural differences in specific recognition.

Science.gov (United States)

Paige, Laura E; Amado, Selen; Gutchess, Angela H

2017-10-01

Prior cross-cultural research has reported cultural variations in memory. One study revealed that Americans remembered images with more perceptual detail than East Asians (Millar et al. in Cult Brain 1(2-4):138-157, 2013). However, in a later study, this expected pattern was not replicated, possibly due to differences in encoding instructions (Paige et al. in Cortex 91:250-261, 2017). The present study sought to examine when cultural variation in memory-related decisions occur and the role of instructions. American and East Asian participants viewed images of objects while making a Purchase decision or an Approach decision and later completed a surprise recognition test. Results revealed Americans had higher hit rates for specific memory, regardless of instruction type, and a less stringent response criterion relative to East Asians. Additionally, a pattern emerged where the Approach decision enhanced hit rates for specific memory relative to the Purchase decision only when administered first; this pattern did not differ across cultures. Results suggest encoding instructions do not magnify cross-cultural differences in memory. Ultimately, cross-cultural differences in response bias, rather than memory sensitivity per se, may account for findings of cultural differences in memory specificity.

Debiasing the Dark Energy Survey's Search for Trans-Neptunian Objects

Science.gov (United States)

Napier, Kevin; Gerdes, David

2018-01-01

The Dark Energy Survey (DES) is rich in transient detections of trans-Neptunian objects (TNOs). This has resulted in many newly detected TNOs. It is important to be mindful that astronomical surveys are intrinsically biased in their detections. Understanding a survey’s bias is necessary to understand the significance of any clustering in the orbital parameters of our detections. To quantify this bias, we examine the DES’s selection function for the detection of TNOs. To do so, we developed a survey simulator in Python. We generate clones of known TNOs with uniformly varied argument of perihelion, longitude of ascending node, and mean anomaly. We test the detectability of each clone based on the pointing location and limiting magnitude of each exposure in DES. Our preliminary results show that our simulator is functional. However, we do not yet have any conclusions about the DES’s bias, as we have not yet run the simulator on the entirety of DES for all of our TNOs.

Effects of viscosity on magnetohydrodynamic behaviour during limiter biasing on the CT-6B tokamak

International Nuclear Information System (INIS)

Khorshid, P.; Wang, L.; Yang, X.Z.; Feng, C.H.; Ghoranneviss, M.

2005-01-01

Effects of viscosity on magnetohydrodynamics behaviour during limiter biasing in the CT-6B Tokamak has been investigated. The results shown that subsequent to the application of a positive bias, a decrease followed by an increase in the frequency of magnetic field fluctuations was observed. With contribution of viscous force effects in the radial force balance equation for Limiter Biasing, in terms of the nonstationarity model, it allows us to identify the understanding physics responsible for change in the Mirnov oscillations that could be related to poloidal rotation velocity and radial electric field. It could be seen that the time scale of responses to biasing is important. The response of ∇p i , decrease of poloidal rotation velocity, the edge electrostatics and magnetic fluctuations to external field have been investigated. The results shown that momentum balance equation with considering viscous force term can be use for modeling of limiter biasing in the tokamak. (author)

The strange case of online surveys: response issues and respondent characteristics

DEFF Research Database (Denmark)

Adamsen, Jannie Mia; Rundle-Thiele, Sharyn; Mehnert, Christina

This research contributes to existing knowledge about collecting data online by analysing multiple data sets on key criteria including overall representativeness of the samples, response and break-off rates, timeliness of response and reminder effects. Across eight online surveys that initially......-30 years of age), single or in ‘other’ types of family relationships, and belong to a low-income bracket (annual household income ... a reminder 48-72 hours after the initial invitation and closing the survey one to two days later; based on our results this time-wise approach still captures 90% of respondents. This study must be viewed in light of some key limitations. Firstly, we have not considered whether there are differences...

Stereotype threat engenders neural attentional bias toward negative feedback to undermine performance.

Science.gov (United States)

Forbes, Chad E; Leitner, Jordan B

2014-10-01

Stereotype threat, a situational pressure individuals experience when they fear confirming a negative group stereotype, engenders a cascade of physiological stress responses, negative appraisals, and performance monitoring processes that tax working memory resources necessary for optimal performance. Less is known, however, about how stereotype threat biases attentional processing in response to performance feedback, and how such attentional biases may undermine performance. Women received feedback on math problems in stereotype threatening compared to stereotype-neutral contexts while continuous EEG activity was recorded. Findings revealed that stereotype threatened women elicited larger midline P100 ERPs, increased phase locking between anterior cingulate cortex and dorsolateral prefrontal cortex (two regions integral for attentional processes), and increased power in left fusiform gyrus in response to negative feedback compared to positive feedback and women in stereotype-neutral contexts. Increased power in left fusiform gyrus in response to negative feedback predicted underperformance on the math task among stereotype threatened women only. Women in stereotype-neutral contexts exhibited the opposite trend. Findings suggest that in stereotype threatening contexts, neural networks integral for attention and working memory are biased toward negative, stereotype confirming feedback at very early speeds of information processing. This bias, in turn, plays a role in undermining performance. Copyright © 2014 Elsevier B.V. All rights reserved.

Opinions and potential solutions regarding dissemination bias from funding agencies of biomedical research in Europe.

Science.gov (United States)

Pardo-Hernandez, Hector; Urrútia, Gerard; Meerpohl, Joerg J; Marušić, Ana; Wager, Elizabeth; Bonfill, Xavier

2018-02-01

Several studies have found that about half of research results from clinical trials are never published. Until now, there has been little information on the views that funding agencies of biomedical research in Europe have regarding this issue and its possible solutions. An electronic survey was conducted among funding agencies from 34 European countries. Participants were asked about their opinions, policies, and potential solutions regarding dissemination bias. On the basis of the results of this survey and the input of the OPEN Consortium and of representatives of stakeholder groups in the knowledge generation process, we formulated recommendations for funding agencies to reduce dissemination bias. We received responses from 64 funding agencies of biomedical medicine from most European countries, out of 245 that were contacted (26%). Of these, 56 funded research at the national and/or international level and were therefore eligible to participate. Policies encouraging publication increased over time: 33 (58.9%) of agencies enforced them in 2005 compared to 38 (67.6%) in 2012. However, only 13 (23.2%) had knowledge of the publications related to research funded in 2005, 23 (41.1%) were able to provide only an estimate, and 20 (35.7%) did not know at all. Regarding recommendations to control dissemination bias, we propose that funding agencies request the dissemination of research results irrespective of the direction of findings. We also call for measures that allow evaluating funded projects past the contractual period and until dissemination of results. Funding agencies should create publicly accessible databases with information on funded projects and dissemination efforts. Despite having policies to encourage publication of results, most funding agencies fail to implement such measures or to ensure compliance. We propose recommendations that could be incorporated in the blueprint of calls for proposals and contracts agreed upon by funding agencies and grant

Biased lineup instructions and face identification from video images.

Science.gov (United States)

Thompson, W Burt; Johnson, Jaime

2008-01-01

Previous eyewitness memory research has shown that biased lineup instructions reduce identification accuracy, primarily by increasing false-positive identifications in target-absent lineups. Because some attempts at identification do not rely on a witness's memory of the perpetrator but instead involve matching photos to images on surveillance video, the authors investigated the effects of biased instructions on identification accuracy in a matching task. In Experiment 1, biased instructions did not affect the overall accuracy of participants who used video images as an identification aid, but nearly all correct decisions occurred with target-present photo spreads. Both biased and unbiased instructions resulted in high false-positive rates. In Experiment 2, which focused on video-photo matching accuracy with target-absent photo spreads, unbiased instructions led to more correct responses (i.e., fewer false positives). These findings suggest that investigators should not relax precautions against biased instructions when people attempt to match photos to an unfamiliar person recorded on video.

Exchange bias mediated by interfacial nanoparticles (invited)

Energy Technology Data Exchange (ETDEWEB)

Berkowitz, A. E., E-mail: aberk@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Center for Magnetic Recording Research, University of California, California 92093 (United States); Sinha, S. K. [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Fullerton, E. E. [Center for Magnetic Recording Research, University of California, California 92093 (United States); Smith, D. J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

2015-05-07

The objective of this study on the iconic exchange-bias bilayer Permalloy/CoO has been to identify those elements of the interfacial microstructure and accompanying magnetic properties that are responsible for the exchange-bias and hysteretic properties of this bilayer. Both epitaxial and polycrystalline samples were examined. X-ray and neutron reflectometry established that there existed an interfacial region, of width ∼1 nm, whose magnetic properties differed from those of Py or CoO. A model was developed for the interfacial microstructure that predicts all the relevant properties of this system; namely; the temperature and Permalloy thickness dependence of the exchange-bias, H{sub EX}, and coercivity, H{sub C}; the much smaller measured values of H{sub EX} from what was nominally expected; the different behavior of H{sub EX} and H{sub C} in epitaxial and polycrystalline bilayers. A surprising result is that the exchange-bias does not involve direct exchange-coupling between Permalloy and CoO, but rather is mediated by CoFe{sub 2}O{sub 4} nanoparticles in the interfacial region.

Bias-Voltage Stabilizer for HVHF Amplifiers in VHF Pulse-Echo Measurement Systems.

Science.gov (United States)

Choi, Hojong; Park, Chulwoo; Kim, Jungsuk; Jung, Hayong

2017-10-23

The impact of high-voltage-high-frequency (HVHF) amplifiers on echo-signal quality is greater with very-high-frequency (VHF, ≥100 MHz) ultrasound transducers than with low-frequency (LF, ≤15 MHz) ultrasound transducers. Hence, the bias voltage of an HVHF amplifier must be stabilized to ensure stable echo-signal amplitudes. We propose a bias-voltage stabilizer circuit to maintain stable DC voltages over a wide input range, thus reducing the harmonic-distortion components of the echo signals in VHF pulse-echo measurement systems. To confirm the feasibility of the bias-voltage stabilizer, we measured and compared the deviations in the gain of the HVHF amplifier with and without a bias-voltage stabilizer. Between -13 and 26 dBm, the measured gain deviations of a HVHF amplifier with a bias-voltage stabilizer are less than that of an amplifier without a bias-voltage stabilizer. In order to confirm the feasibility of the bias-voltage stabilizer, we compared the pulse-echo responses of the amplifiers, which are typically used for the evaluation of transducers or electronic components used in pulse-echo measurement systems. From the responses, we observed that the amplitudes of the echo signals of a VHF transducer triggered by the HVHF amplifier with a bias-voltage stabilizer were higher than those of the transducer triggered by the HVHF amplifier alone. The second, third, and fourth harmonic-distortion components of the HVHF amplifier with the bias-voltage stabilizer were also lower than those of the HVHF amplifier alone. Hence, the proposed scheme is a promising method for stabilizing the bias voltage of an HVHF amplifier, and improving the echo-signal quality of VHF transducers.

The use of advanced web-based survey design in Delphi research.

Science.gov (United States)

Helms, Christopher; Gardner, Anne; McInnes, Elizabeth

2017-12-01

A discussion of the application of metadata, paradata and embedded data in web-based survey research, using two completed Delphi surveys as examples. Metadata, paradata and embedded data use in web-based Delphi surveys has not been described in the literature. The rapid evolution and widespread use of online survey methods imply that paper-based Delphi methods will likely become obsolete. Commercially available web-based survey tools offer a convenient and affordable means of conducting Delphi research. Researchers and ethics committees may be unaware of the benefits and risks of using metadata in web-based surveys. Discussion paper. Two web-based, three-round Delphi surveys were conducted sequentially between August 2014 - January 2015 and April - May 2016. Their aims were to validate the Australian nurse practitioner metaspecialties and their respective clinical practice standards. Our discussion paper is supported by researcher experience and data obtained from conducting both web-based Delphi surveys. Researchers and ethics committees should consider the benefits and risks of metadata use in web-based survey methods. Web-based Delphi research using paradata and embedded data may introduce efficiencies that improve individual participant survey experiences and reduce attrition across iterations. Use of embedded data allows the efficient conduct of multiple simultaneous Delphi surveys across a shorter timeframe than traditional survey methods. The use of metadata, paradata and embedded data appears to improve response rates, identify bias and give possible explanation for apparent outlier responses, providing an efficient method of conducting web-based Delphi surveys. © 2017 John Wiley & Sons Ltd.

Conducting Web-based Surveys.

OpenAIRE

David J. Solomon

2001-01-01

Web-based surveying is becoming widely used in social science and educational research. The Web offers significant advantages over more traditional survey techniques however there are still serious methodological challenges with using this approach. Currently coverage bias or the fact significant numbers of people do not have access, or choose not to use the Internet is of most concern to researchers. Survey researchers also have much to learn concerning the most effective ways to conduct s...

The 'male escape hypothesis': sex-biased metamorphosis in response to climatic drivers in a facultatively paedomorphic amphibian.

Science.gov (United States)

Mathiron, Anthony G E; Lena, Jean-Paul; Baouch, Sarah; Denoël, Mathieu

2017-04-26

Paedomorphosis is a major evolutionary process that bypasses metamorphosis and allows reproduction in larvae. In newts and salamanders, it can be facultative with paedomorphs retaining gills and metamorphs dispersing. The evolution of these developmental processes is thought to have been driven by the costs and benefits of inhabiting aquatic versus terrestrial habitats. In this context, we aimed at testing the hypothesis that climatic drivers affect phenotypic transition and the difference across sexes because sex-ratio is biased in natural populations. Through a replicated laboratory experiment, we showed that paedomorphic palmate newts ( Lissotriton helveticus ) metamorphosed at a higher frequency when water availability decreased and metamorphosed earlier when temperature increased in these conditions. All responses were sex-biased, and males were more prone to change phenotype than females. Our work shows how climatic variables can affect facultative paedomorphosis and support theoretical models predicting life on land instead of in water. Moreover, because males metamorphose and leave water more often and earlier than females, these results, for the first time, give an experimental explanation for the rarity of male paedomorphosis (the 'male escape hypothesis') and suggest the importance of sex in the evolution of paedomorphosis versus metamorphosis. © 2017 The Author(s).

Accounting for response misclassification and covariate measurement error improves power and reduces bias in epidemiologic studies.

Science.gov (United States)

Cheng, Dunlei; Branscum, Adam J; Stamey, James D

2010-07-01

To quantify the impact of ignoring misclassification of a response variable and measurement error in a covariate on statistical power, and to develop software for sample size and power analysis that accounts for these flaws in epidemiologic data. A Monte Carlo simulation-based procedure is developed to illustrate the differences in design requirements and inferences between analytic methods that properly account for misclassification and measurement error to those that do not in regression models for cross-sectional and cohort data. We found that failure to account for these flaws in epidemiologic data can lead to a substantial reduction in statistical power, over 25% in some cases. The proposed method substantially reduced bias by up to a ten-fold margin compared to naive estimates obtained by ignoring misclassification and mismeasurement. We recommend as routine practice that researchers account for errors in measurement of both response and covariate data when determining sample size, performing power calculations, or analyzing data from epidemiological studies. 2010 Elsevier Inc. All rights reserved.

Would you say "yes" in the evening? Time-of-day effect on response bias in four types of working memory recognition tasks.

Science.gov (United States)

Lewandowska, Koryna; Wachowicz, Barbara; Marek, Tadeusz; Oginska, Halszka; Fafrowicz, Magdalena

2018-01-01

Across a wide range of tasks, cognitive functioning is affected by circadian fluctuations. In this study, we investigated diurnal variations of working memory performance, taking into account not only hits and errors rates, but also sensitivity (d') and response bias (c) indexes (established by signal detection theory). Fifty-two healthy volunteers performed four experimental tasks twice - in the morning and in the evening (approximately 1 and 10 h after awakening). All tasks were based on Deese-Roediger-McDermott paradigm version dedicated to study working/short-term memory distortions. Participants were to memorize sets of stimuli characterized by either conceptual or perceptual similarity, and to answer if they recognized subsequent stimulus (probe) as an "old" one (i.e. presented in the preceding memory set). The probe was of three types: positive, negative or related lure. In two verbal tasks, memory sets were characterized by semantic or phonological similarity. In two visual tasks, abstract objects were characterized by a number of overlapping similarities or differed in only one detail. The type of experimental material and the participants' diurnal preference were taken into account. The analysis showed significant effect of time of day on false alarms rate (F (1,50)  = 5.29, p = 0.03, η p 2  = 0.1) and response bias (F (1,50)  = 11.16, p = 0.002, η p 2  = 0.18). In other words, in the evening participants responded in more liberal way than in the morning (answering "yes" more often). As the link between variations in false alarms rate, response bias and locus coeruleus activity was indicated in literature before, we believe that our data may be interpreted as supporting the hypothesis that diurnal fluctuations in norepinephrine release have effect on cognitive functioning in terms of decision threshold.

Measuring fertility through mobile‒phone based household surveys: Methods, data quality, and lessons learned from PMA2020 surveys

Directory of Open Access Journals (Sweden)

Yoonjoung Choi

2018-05-01

Full Text Available Background: PMA2020 is a survey platform with resident enumerators using mobile phones. Instead of collecting full birth history, total fertility rates (TFR have been measured with a limited number of questions on recent births. Employing new approaches provides opportunities to test and advance survey methods. Objective: This study aims to assess the quality of fertility data in PMA2020 surveys, focusing on bias introduced from the questionnaire and completeness and distribution of birth month and year, and to estimate TFR adjusted for identified data quality issues. Methods: To assess underestimation from the questionnaire, we simulated births that would be counted using the PMA2020 questionnaires compared to births identified from full birth history. We analyzed the latest Demographic and Health Surveys in ten countries where PMA2020 surveys have been implemented. We assessed the level of reporting completeness for birth month and year and heaping of birth month, analyzing 39 PMA2020 surveys. Finally, TFR were calculated and adjusted for biases introduced from the questionnaire and heaping in birth month. Results: Simple questions introduced minor bias from undercounting multiple births, which was expected and correctable. Meanwhile, incomplete reporting of birth month was relatively high, and the default value of January in data collection software systematically moved births with missing months out of the reference period. On average across the 39 surveys, TFR increased by 1.6Š and 2.4Š, adjusted for undercounted multiple births and heaping on January, respectively. Contribution: This study emphasizes the importance of enumerator training and provides critical insight in software programming in surveys using mobile technologies.

"The impact of uncertain threat on affective bias: Individual differences in response to ambiguity": Correction.

Science.gov (United States)

2018-04-01

Reports an error in "The impact of uncertain threat on affective bias: Individual differences in response to ambiguity" by Maital Neta, Julie Cantelon, Zachary Haga, Caroline R. Mahoney, Holly A. Taylor and F. Caroline Davis ( Emotion , 2017[Dec], Vol 17[8], 1137-1143). In this article, the copyright attribution was incorrectly listed under the Creative Commons CC-BY license due to production-related error. The correct copyright should be "In the public domain." The online version of this article has been corrected. (The following abstract of the original article appeared in record 2017-40275-001.) Individuals who operate under highly stressful conditions (e.g., military personnel and first responders) are often faced with the challenge of quickly interpreting ambiguous information in uncertain and threatening environments. When faced with ambiguity, it is likely adaptive to view potentially dangerous stimuli as threatening until contextual information proves otherwise. One laboratory-based paradigm that can be used to simulate uncertain threat is known as threat of shock (TOS), in which participants are told that they might receive mild but unpredictable electric shocks while performing an unrelated task. The uncertainty associated with this potential threat induces a state of emotional arousal that is not overwhelmingly stressful, but has widespread-both adaptive and maladaptive-effects on cognitive and affective function. For example, TOS is thought to enhance aversive processing and abolish positivity bias. Importantly, in certain situations (e.g., when walking home alone at night), this anxiety can promote an adaptive state of heightened vigilance and defense mobilization. In the present study, we used TOS to examine the effects of uncertain threat on valence bias, or the tendency to interpret ambiguous social cues as positive or negative. As predicted, we found that heightened emotional arousal elicited by TOS was associated with an increased tendency to

New Trends in Magnetic Exchange Bias

Science.gov (United States)

Mougin, Alexandra; Mangin, Stéphane; Bobo, Jean-Francois; Loidl, Alois

2005-05-01

of the constituant layers. The spirit of this topical issue is, for the first time, to gather and survey recent and original developments, both experimental and theoretical, which bring new insights into the physics of exchange bias. It has been planned in relation with an international workshop exclusively devoted to exchange bias, namely IWEBMN’04 (International Workshop on Exchange Bias in Magnetic Nanostructures) that took place in Anglet, in the south west of France, from 16th to 18th September 2004. The conference gathered worldwide researchers in the area, both experimentalists and theoreticians. Several research paths are particularly active in the field of magnetic exchange coupling. The conference, as well as this topical issue, which was also open to contributions from scientists not participating in the conference, has been organized according to the following principles: 1. Epitaxial systems: Since the essential behavior of exchange bias critically depends on the atomic-level chemical and spin structure at the interface between the ferromagnetic and antiferromagnetic components, epitaxial AF/F systems in which the quality of the interface and the crystalline coherence are optimized and well known are ideal candidates for a better understanding of the underlying physics of exchange bias. The dependence of exchange bias on the spin configurations at the interfaces can be accomplished by selecting different crystallographic orientations. The role of interface roughness can also be understood from thin-film systems by changing the growth parameters, and correlations between the interface structure and exchange bias can be made, as reported in this issue. 2. Out-of-plane magnetized systems: While much important work has been devoted to the study of structures with in-plane magnetization, little has been done on the study of exchange bias and exchange coupling in samples with out-of-plane magnetization. Some systems can exhibit either in-plane or out

In Search of Motivation for the Business Survey Response Task

OpenAIRE

Torres van Grinsven Vanessa; Bolko Irena; Bavdaž Mojca

2014-01-01

Increasing reluctance of businesses to participate in surveys often leads to declining or low response rates, poor data quality and burden complaints, and suggests that a driving force, that is, the motivation for participation and accurate and timely response, is insufficient or lacking. Inspiration for ways to remedy this situation has already been sought in the psychological theory of self-determination; previous research has favored enhancement of intrinsic motivation compared to extrinsi...

How does the cosmic web impact assembly bias?

Science.gov (United States)

Musso, M.; Cadiou, C.; Pichon, C.; Codis, S.; Kraljic, K.; Dubois, Y.

2018-06-01

The mass, accretion rate, and formation time of dark matter haloes near protofilaments (identified as saddle points of the potential) are analytically predicted using a conditional version of the excursion set approach in its so-called upcrossing approximation. The model predicts that at fixed mass, mass accretion rate and formation time vary with orientation and distance from the saddle, demonstrating that assembly bias is indeed influenced by the tides imposed by the cosmic web. Starved, early-forming haloes of smaller mass lie preferentially along the main axis of filaments, while more massive and younger haloes are found closer to the nodes. Distinct gradients for distinct tracers such as typical mass and accretion rate occur because the saddle condition is anisotropic, and because the statistics of these observables depend on both the conditional means and their covariances. The theory is extended to other critical points of the potential field. The response of the mass function to variations of the matter density field (the so-called large-scale bias) is computed, and its trend with accretion rate is shown to invert along the filament. The signature of this model should correspond at low redshift to an excess of reddened galactic hosts at fixed mass along preferred directions, as recently reported in spectroscopic and photometric surveys and in hydrodynamical simulations. The anisotropy of the cosmic web emerges therefore as a significant ingredient to describe jointly the dynamics and physics of galaxies, e.g. in the context of intrinsic alignments or morphological diversity.

Continuous carryover of temporal context dissociates response bias from perceptual influence for duration.

Directory of Open Access Journals (Sweden)

Martin Wiener

Full Text Available Recent experimental evidence suggests that the perception of temporal intervals is influenced by the temporal context in which they are presented. A longstanding example is the time-order-error, wherein the perception of two intervals relative to one another is influenced by the order in which they are presented. Here, we test whether the perception of temporal intervals in an absolute judgment task is influenced by the preceding temporal context. Human subjects participated in a temporal bisection task with no anchor durations (partition method. Intervals were demarcated by a Gaussian blob (visual condition or burst of white noise (auditory condition that persisted for one of seven logarithmically spaced sub-second intervals. Crucially, the order in which stimuli were presented was first-order counterbalanced, allowing us to measure the carryover effect of every successive combination of intervals. The results demonstrated a number of distinct findings. First, the perception of each interval was biased by the prior response, such that each interval was judged similarly to the preceding trial. Second, the perception of each interval was also influenced by the prior interval, such that perceived duration shifted away from the preceding interval. Additionally, the effect of decision bias was larger for visual intervals, whereas auditory intervals engendered greater perceptual carryover. We quantified these effects by designing a biologically-inspired computational model that measures noisy representations of time against an adaptive memory prior while simultaneously accounting for uncertainty, consistent with a Bayesian heuristic. We found that our model could account for all of the effects observed in human data. Additionally, our model could only accommodate both carryover effects when uncertainty and memory were calculated separately, suggesting separate neural representations for each. These findings demonstrate that time is susceptible to

Sample Loss and Survey Bias in Estimates of Social Security Beneficiaries: A Tale of Two Surveys.

OpenAIRE

John L. Czajka; James Mabli; Scott Cody

2008-01-01

Data from the Census Bureau’s Survey of Income and Program Participation (SIPP) and the Current Population Survey (CPS) provide information on current and potential beneficiaries served by Social Security Administration (SSA) programs. SSA also links administrative records to the records of survey respondents who provide Social Security numbers. These matched data expand the content of the SIPP and CPS files to fields available only through SSA and Internal Revenue Service records—such as l...

A Case Study of Gender Bias at the Postdoctoral Level in Physics ...

Indian Academy of Sciences (India)

2008-04-17

Apr 17, 2008 ... ... data for such studies unfortunately carries the dangers of survey bias. .... internet, we compiled a list of past postdoctoral researchers on the Run II ... from the internet included, amongst other things, vitae and/or current.

The effect of health, socio-economic position, and mode of data collection on non-response in health interview surveys

DEFF Research Database (Denmark)

Ekholm, Ola; Gundgaard, Jens; Rasmussen, Niels K R

2010-01-01

AIMS: To investigate the relationship between potential explanatory factors (socio-economic factors and health) and non-response in two general population health interview surveys (face-to-face and telephone), and to compare the effects of the two interview modes on non-response patterns. METHODS...... in health interview surveys, but the non-response rate is higher in lower socio-economic groups. Analyses of non-response should be performed to understand the implications of survey findings.......: Data derives from The Danish Health Interview Survey 2000 (face-to-face interview) and The Funen County Health Survey 2000/2001 (telephone interview). Data on all invited individuals were obtained from administrative registers and linked to survey data at individual level. Multiple logistic regression...

Semi-automatic long-term acoustic surveying

DEFF Research Database (Denmark)

Andreassen, Tórur; Surlykke, Annemarie; Hallam, John

2014-01-01

Increasing concern about decline in biodiversity has created a demand for population surveys. Acoustic monitoring is an efficient non-invasive method, which may be deployed for surveys of animals as diverse as insects, birds, and bats. Long-term unmanned automatic monitoring may provide unique...... to determine bat behavior and correct for the bias toward loud bats inherent in acoustic surveying....

Bias in employment decisions about mothers and fathers: The (dis)advantages of sharing care responsibilities

NARCIS (Netherlands)

Vinkenburg, C.J.; Van Engen, M.L.; Coffeng, J.; Dikkers, J.S.E.

2012-01-01

Bias against mothers in employment decisions has often been explained by the assumption that mothers are less committed and competent than fathers and nonparents. In a simulated employment context, we studied whether this "motherhood bias" can be attenuated by different ways of dividing care

Traumatogenic Processes and Pathways to Mental Health Outcomes for Sexual Minorities Exposed to Bias Crime Information.

Science.gov (United States)

Lannert, Brittany K

2015-07-01

Vicarious traumatization of nonvictim members of communities targeted by bias crimes has been suggested by previous qualitative studies and often dominates public discussion following bias events, but proximal and distal responses of community members have yet to be comprehensively modeled, and quantitative research on vicarious responses is scarce. This comprehensive review integrates theoretical and empirical literatures in social, clinical, and physiological psychology in the development of a model of affective, cognitive, and physiological responses of lesbian, gay, and bisexual individuals upon exposure to information about bias crimes. Extant qualitative research in vicarious response to bias crimes is reviewed in light of theoretical implications and methodological limitations. Potential pathways to mental health outcomes are outlined, including accumulative effects of anticipatory defensive responding, multiplicative effects of minority stress, and putative traumatogenic physiological and cognitive processes of threat. Methodological considerations, future research directions, and clinical implications are also discussed. © The Author(s) 2014.

Corporate Social Responsibility in Engineering Education. A French Survey

Science.gov (United States)

Didier, C.; Huet, R.

2008-01-01

In this paper, we present and discuss the results of a survey of how corporate social responsibility (CSR) is being discussed and taught in engineering education in France. We shall first describe how those questions have been recently tackled in various programmes of higher education in France. We shall also analyse what faculty members have to…

Biased selection within the social health insurance market in Colombia.

Science.gov (United States)

Castano, Ramon; Zambrano, Andres

2006-12-01

Reducing the impact of insurance market failures with regulations such as community-rated premiums, standardized benefit packages and open enrolment, yield limited effect because they create room for selection bias. The Colombian social health insurance system started a market approach in 1993 expecting to improve performance of preexisting monopolistic insurance funds by exposing them to competition by new entrants. This paper tests the hypothesis that market failures would lead to biased selection favoring new entrants. Two household surveys are analyzed using Self-Reported Health Status and the presence of chronic conditions as prospective indicators of individual risk. Biased selection is found to take place, leading to adverse selection among incumbents, and favorable selection among new entrants. This pattern is absent in 1997 but is evident in 2003. Given that the two incumbents analyzed are public organizations, the fiscal implications of the findings in terms of government bailouts, are analyzed.

Attentional Bias to Food Cues in Youth with Loss of Control Eating

Science.gov (United States)

2016-05-20

Vollstadt-Klein S, et al. 2012. Impairment of inhibitory control in response to food - associated cues and attentional bias of obese participants...on the obesity epidemic? Int. J. Eat. Disord. 34:S117-20 104. Yokum S, Ng J, Stice E. 2011. Attentional bias to food images associated with...bias toward high palatable foods versus neutral objects was positively associated with BMI-z. These findings suggest that LOC eating and body weight

The Belief Bias Effect Is Aptly Named: A Reply to Klauer and Kellen (2011)

Science.gov (United States)

Dube, Chad; Rotello, Caren M.; Heit, Evan

2011-01-01

In "Assessing the Belief Bias Effect With ROCs: It's a Response Bias Effect," Dube, Rotello, and Heit (2010) examined the form of receiver operating characteristic (ROC) curves for reasoning and the effects of belief bias on measurement indices that differ in whether they imply a curved or linear ROC function. We concluded that the ROC…

Frequency Response Analysis Tool

Energy Technology Data Exchange (ETDEWEB)

Etingov, Pavel V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kosterev, Dmitry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dai, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-12-01

Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

Implicit Bias and Mental Health Professionals: Priorities and Directions for Research.

Science.gov (United States)

Merino, Yesenia; Adams, Leslie; Hall, William J

2018-06-01

This Open Forum explores the role of implicit bias along the mental health care continuum, which may contribute to mental health disparities among vulnerable populations. Emerging research shows that implicit bias is prevalent among service providers. These negative or stigmatizing attitudes toward population groups are held at a subconscious level and are automatically activated during practitioner-client encounters. The authors provide examples of how implicit bias may impede access to care, clinical screening and diagnosis, treatment processes, and crisis response. They also discuss how implicit attitudes may manifest at the intersection between mental health and criminal justice institutions. Finally, they discuss the need for more research on the impact of implicit bias on health practices throughout the mental health system, including the development of interventions to address implicit bias among mental health professionals.

Bioinspired Intelligent Algorithm and Its Applications for Mobile Robot Control: A Survey

Science.gov (United States)

Ni, Jianjun; Wu, Liuying; Fan, Xinnan; Yang, Simon X.

2016-01-01

Bioinspired intelligent algorithm (BIA) is a kind of intelligent computing method, which is with a more lifelike biological working mechanism than other types. BIAs have made significant progress in both understanding of the neuroscience and biological systems and applying to various fields. Mobile robot control is one of the main application fields of BIAs which has attracted more and more attention, because mobile robots can be used widely and general artificial intelligent algorithms meet a development bottleneck in this field, such as complex computing and the dependence on high-precision sensors. This paper presents a survey of recent research in BIAs, which focuses on the research in the realization of various BIAs based on different working mechanisms and the applications for mobile robot control, to help in understanding BIAs comprehensively and clearly. The survey has four primary parts: a classification of BIAs from the biomimetic mechanism, a summary of several typical BIAs from different levels, an overview of current applications of BIAs in mobile robot control, and a description of some possible future directions for research. PMID:26819582

Bioinspired Intelligent Algorithm and Its Applications for Mobile Robot Control: A Survey.

Science.gov (United States)

Ni, Jianjun; Wu, Liuying; Fan, Xinnan; Yang, Simon X

2016-01-01

Bioinspired intelligent algorithm (BIA) is a kind of intelligent computing method, which is with a more lifelike biological working mechanism than other types. BIAs have made significant progress in both understanding of the neuroscience and biological systems and applying to various fields. Mobile robot control is one of the main application fields of BIAs which has attracted more and more attention, because mobile robots can be used widely and general artificial intelligent algorithms meet a development bottleneck in this field, such as complex computing and the dependence on high-precision sensors. This paper presents a survey of recent research in BIAs, which focuses on the research in the realization of various BIAs based on different working mechanisms and the applications for mobile robot control, to help in understanding BIAs comprehensively and clearly. The survey has four primary parts: a classification of BIAs from the biomimetic mechanism, a summary of several typical BIAs from different levels, an overview of current applications of BIAs in mobile robot control, and a description of some possible future directions for research.

Bioinspired Intelligent Algorithm and Its Applications for Mobile Robot Control: A Survey

Directory of Open Access Journals (Sweden)

Jianjun Ni

2016-01-01

Full Text Available Bioinspired intelligent algorithm (BIA is a kind of intelligent computing method, which is with a more lifelike biological working mechanism than other types. BIAs have made significant progress in both understanding of the neuroscience and biological systems and applying to various fields. Mobile robot control is one of the main application fields of BIAs which has attracted more and more attention, because mobile robots can be used widely and general artificial intelligent algorithms meet a development bottleneck in this field, such as complex computing and the dependence on high-precision sensors. This paper presents a survey of recent research in BIAs, which focuses on the research in the realization of various BIAs based on different working mechanisms and the applications for mobile robot control, to help in understanding BIAs comprehensively and clearly. The survey has four primary parts: a classification of BIAs from the biomimetic mechanism, a summary of several typical BIAs from different levels, an overview of current applications of BIAs in mobile robot control, and a description of some possible future directions for research.

Estimates of bias and uncertainty in recorded external dose

International Nuclear Information System (INIS)

Fix, J.J.; Gilbert, E.S.; Baumgartner, W.V.

1994-10-01

A study is underway to develop an approach to quantify bias and uncertainty in recorded dose estimates for workers at the Hanford Site based on personnel dosimeter results. This paper focuses on selected experimental studies conducted to better define response characteristics of Hanford dosimeters. The study is more extensive than the experimental studies presented in this paper and includes detailed consideration and evaluation of other sources of bias and uncertainty. Hanford worker dose estimates are used in epidemiologic studies of nuclear workers. A major objective of these studies is to provide a direct assessment of the carcinogenic risk of exposure to ionizing radiation at low doses and dose rates. Considerations of bias and uncertainty in the recorded dose estimates are important in the conduct of this work. The method developed for use with Hanford workers can be considered an elaboration of the approach used to quantify bias and uncertainty in estimated doses for personnel exposed to radiation as a result of atmospheric testing of nuclear weapons between 1945 and 1962. This approach was first developed by a National Research Council (NRC) committee examining uncertainty in recorded film badge doses during atmospheric tests (NRC 1989). It involved quantifying both bias and uncertainty from three sources (i.e., laboratory, radiological, and environmental) and then combining them to obtain an overall assessment. Sources of uncertainty have been evaluated for each of three specific Hanford dosimetry systems (i.e., the Hanford two-element film dosimeter, 1944-1956; the Hanford multi-element film dosimeter, 1957-1971; and the Hanford multi-element TLD, 1972-1993) used to estimate personnel dose throughout the history of Hanford operations. Laboratory, radiological, and environmental sources of bias and uncertainty have been estimated based on historical documentation and, for angular response, on selected laboratory measurements

Pyroelectric response mechanism of barium strontium titanate ceramics in dielectric bolometer mode: The underlying essence of the enhancing effect of direct current bias field

International Nuclear Information System (INIS)

Mao, Chaoliang; Cao, Sheng; Yan, Shiguang; Yao, Chunhua; Cao, Fei; Wang, Genshui; Dong, Xianlin; Hu, Xu; Yang, Chunli

2013-01-01

Pyroelectric response mechanism of Ba 0.70 Sr 0.30 TiO 3 ceramics under dielectric bolometer (DB) mode was investigated by dielectric and pyroelectric properties measurement. The variations of total, intrinsic, and induced pyroelectric coefficients (p tot , p int , p ind ) with temperatures and bias fields were analyzed. p int plays the dominant role to p tot through most of the temperature range and p ind will be slightly higher than p int above T 0 . The essence of the enhancing effect of DC bias field on pyroelectric coefficient can be attributed to the high value of p int . This mechanism is useful for the pyroelectric materials (DB mode) applications.

Measurement Error in Income and Schooling and the Bias of Linear Estimators

DEFF Research Database (Denmark)

Bingley, Paul; Martinello, Alessandro

2017-01-01

and Retirement in Europe data with Danish administrative registers. Contrary to most validation studies, we find that measurement error in income is classical once we account for imperfect validation data. We find nonclassical measurement error in schooling, causing a 38% amplification bias in IV estimators......We propose a general framework for determining the extent of measurement error bias in ordinary least squares and instrumental variable (IV) estimators of linear models while allowing for measurement error in the validation source. We apply this method by validating Survey of Health, Ageing...

An algorithm to assess methodological quality of nutrition and mortality cross-sectional surveys: development and application to surveys conducted in Darfur, Sudan.

Science.gov (United States)

Prudhon, Claudine; de Radiguès, Xavier; Dale, Nancy; Checchi, Francesco

2011-11-09

Nutrition and mortality surveys are the main tools whereby evidence on the health status of populations affected by disasters and armed conflict is quantified and monitored over time. Several reviews have consistently revealed a lack of rigor in many surveys. We describe an algorithm for analyzing nutritional and mortality survey reports to identify a comprehensive range of errors that may result in sampling, response, or measurement biases and score quality. We apply the algorithm to surveys conducted in Darfur, Sudan. We developed an algorithm based on internationally agreed upon methods and best practices. Penalties are attributed for a list of errors, and an overall score is built from the summation of penalties accrued by the survey as a whole. To test the algorithm reproducibility, it was independently applied by three raters on 30 randomly selected survey reports. The algorithm was further applied to more than 100 surveys conducted in Darfur, Sudan. The Intra Class Correlation coefficient was 0.79 for mortality surveys and 0.78 for nutrition surveys. The overall median quality score and range of about 100 surveys conducted in Darfur were 0.60 (0.12-0.93) and 0.675 (0.23-0.86) for mortality and nutrition surveys, respectively. They varied between the organizations conducting the surveys, with no major trend over time. Our study suggests that it is possible to systematically assess quality of surveys and reveals considerable problems with the quality of nutritional and particularly mortality surveys conducted in the Darfur crisis.

Apparent directional selection by biased pleiotropic mutation.

Science.gov (United States)

Tanaka, Yoshinari

2010-07-01

Pleiotropic effects of deleterious mutations are considered to be among the factors responsible for genetic constraints on evolution by long-term directional selection acting on a quantitative trait. If pleiotropic phenotypic effects are biased in a particular direction, mutations generate apparent directional selection, which refers to the covariance between fitness and the trait owing to a linear association between the number of mutations possessed by individuals and the genotypic values of the trait. The present analysis has shown how the equilibrium mean value of the trait is determined by a balance between directional selection and biased pleiotropic mutations. Assuming that genes act additively both on the trait and on fitness, the total variance-standardized directional selection gradient was decomposed into apparent and true components. Experimental data on mutation bias from the bristle traits of Drosophila and life history traits of Daphnia suggest that apparent selection explains a small but significant fraction of directional selection pressure that is observed in nature; the data suggest that changes induced in a trait by biased pleiotropic mutation (i.e., by apparent directional selection) are easily compensated for by (true) directional selection.

A computerized Stroop task to assess cancer-related cognitive biases.

Science.gov (United States)

DiBonaventura, Marco DaCosta; Erblich, Joel; Sloan, Richard P; Bovbjerg, Dana H

2010-01-01

Biases in processing information related to sources of stress have widely been demonstrated with the use of Stroop emotional color word tasks. One study reported such biases among women with histories of breast cancer in a first-degree relative (FH+) who were given a Stroop cancer word task. This study aimed to replicate and extend these findings with a computerized version of the task. Response latencies and errors were recorded during administration of the task to FH+ and FH- women. A cancer list and 5 comparison lists were administered. Results indicated that FH+ women exhibited longer response latencies for cancer words than did FH- women (p Stroop cancer word task.

Magnification bias as a novel probe for primordial magnetic fields

International Nuclear Information System (INIS)

Camera, S.; Fedeli, C.; Moscardini, L.

2014-01-01

In this paper we investigate magnetic fields generated in the early Universe. These fields are important candidates at explaining the origin of astrophysical magnetism observed in galaxies and galaxy clusters, whose genesis is still by and large unclear. Compared to the standard inflationary power spectrum, intermediate to small scales would experience further substantial matter clustering, were a cosmological magnetic field present prior to recombination. As a consequence, the bias and redshift distribution of galaxies would also be modified. Hitherto, primordial magnetic fields (PMFs) have been tested and constrained with a number of cosmological observables, e.g. the cosmic microwave background radiation, galaxy clustering and, more recently, weak gravitational lensing. Here, we explore the constraining potential of the density fluctuation bias induced by gravitational lensing magnification onto the galaxy-galaxy angular power spectrum. Such an effect is known as magnification bias. Compared to the usual galaxy clustering approach, magnification bias helps in lifting the pathological degeneracy present amongst power spectrum normalisation and galaxy bias. This is because magnification bias cross-correlates galaxy number density fluctuations of nearby objects with weak lensing distortions of high-redshift sources. Thus, it takes advantage of the gravitational deflection of light, which is insensitive to galaxy bias but powerful in constraining the density fluctuation amplitude. To scrutinise the potentiality of this method, we adopt a deep and wide-field spectroscopic galaxy survey. We show that magnification bias does contain important information on primordial magnetism, which will be useful in combination with galaxy clustering and shear. We find we shall be able to rule out at 95.4% CL amplitudes of PMFs larger than 5 × 10 −4 nG for values of the PMF power spectral index n B ∼ 0

Pharmacogenomics Bias - Systematic distortion of study results by genetic heterogeneity

Directory of Open Access Journals (Sweden)

Zietemann, Vera

2008-04-01

Full Text Available Background: Decision analyses of drug treatments in chronic diseases require modeling the progression of disease and treatment response beyond the time horizon of clinical or epidemiological studies. In many such models, progression and drug effect have been applied uniformly to all patients; heterogeneity in progression, including pharmacogenomic effects, has been ignored. Objective: We sought to systematically evaluate the existence, direction and relative magnitude of a pharmacogenomics bias (PGX-Bias resulting from failure to adjust for genetic heterogeneity in both treatment response (HT and heterogeneity in progression of disease (HP in decision-analytic studies based on clinical study data. Methods: We performed a systematic literature search in electronic databases for studies regarding the effect of genetic heterogeneity on the validity of study results. Included studies have been summarized in evidence tables. In the case of lacking evidence from published studies we sought to perform our own simulation considering both HT and HP. We constructed two simple Markov models with three basic health states (early-stage disease, late-stage disease, dead, one adjusting and the other not adjusting for genetic heterogeneity. Adjustment was done by creating different disease states for presence (G+ and absence (G- of a dichotomous genetic factor. We compared the life expectancy gains attributable to treatment resulting from both models and defined pharmacogenomics bias as percent deviation of treatment-related life expectancy gains in the unadjusted model from those in the adjusted model. We calculated the bias as a function of underlying model parameters to create generic results. We then applied our model to lipid-lowering therapy with pravastatin in patients with coronary atherosclerosis, incorporating the influence of two TaqIB polymorphism variants (B1 and B2 on progression and drug efficacy as reported in the DNA substudy of the REGRESS

The association between male-biased sex ratio and indicators of stress in red-spotted newts.

Science.gov (United States)

Aspbury, Andrea S; Grayson, Kristine L; Fantaye, Selamawit; Nichols, Ian; Myers-Burton, Miranda; Ortiz-Mangual, Xavier; Gabor, Caitlin R

2017-05-01

In populations with a male-biased operational sex ratio, coercive mating by males can have fitness consequences for females. One component of reduced fitness for females in populations with a male-biased OSR may be greater activation of the stress response, resulting in higher corticosterone release rates (CORT; a glucocorticoid stress hormone in amphibians). We test the hypothesis that a male-biased sex ratio affects female activity and release rates of CORT and testosterone (T) in male and female red-spotted newts (Notophthalmus viridescens). First, we evaluated if chemical cues from a male-biased sex ratio affect activity and CORT release rates in females. We predicted that females exposed to chemical cues of three males would be less active and have higher CORT release rates than those exposed to chemical cues of one male. Second, we measured CORT release rates of red-spotted newts in field enclosures with either a male-biased or a female-biased sex ratio. We predicted that females in the male-biased treatment would have higher CORT and T release rates than those in a female-biased treatment, owing to higher levels of male harassment. We also predicted that males would have higher CORT and T release rates in male-biased treatments due to higher levels of male-male competition. Females were not less active in response to chemical cues from more males over fewer males, but there was a positive relationship between female activity and CORT when they were exposed to the cues of three males. We also found that females, but not males, in the male-biased sex ratio treatment had higher CORT and T release rates than those in the female-biased treatment. Our results support the hypothesis that a male-biased sex ratio leads to a higher stress response, which may underlie the observed decrease in immune function and body condition in previous work exposing female red-spotted newts to a male-biased sex ratio. This study furthers our understanding of the mechanistic basis

Dose-rate effects of low-dropout voltage regulator at various biases

International Nuclear Information System (INIS)

Wang Yiyuan; Zheng Yuzhan; Gao Bo; Chen Rui; Fei Wuxiong; Lu Wu; Ren Diyuan

2010-01-01

A low-dropout voltage regulator, LM2941, was irradiated by 60 Co γ-rays at various dose rates and biases for investigating the total dose and dose rate effects. The radiation responses show that the key electrical parameters, including its output and dropout voltage, and the maximum output current, are sensitive to total dose and dose rates, and are significantly degraded at low dose rate and zero bias. The integrated circuits damage change with the dose rates and biases, and the dose-rate effects are relative to its electric field. (authors)

FROM BIAS TO BISEXUAL HEALTH DISPARITIES: ATTITUDES TOWARD BISEXUAL MEN AND WOMEN IN THE UNITED STATES.

Science.gov (United States)

Friedman, M Reuel; Dodge, Brian; Schick, Vanessa; Herbenick, Debby; Hubach, Randolph; Bowling, Jessamyn; Goncalves, Gabriel; Krier, Sarah; Reece, Michael

2014-12-01

A newly emergent literature suggest that bisexual men and women face profound health disparities in comparison to both heterosexual and homosexual individuals. Additionally, bisexual individuals often experience prejudice, stigma, and discrimination from both gay/lesbian and straight communities, termed "biphobia." However, only limited research exists that empirically tests the extent and predictors of this double discrimination. The Bisexualities: Indiana Attitudes Survey (BIAS) was developed to test associations between biphobia and sexual identity. Using standard techniques, we developed and administered a scale to a purposive online sample of adults from a wide range of social networking websites. We conducted exploratory factor analysis to refine scales assessing attitudes toward bisexual men and bisexual women, respectively. Using generalized linear modeling, we assessed relationships between BIAS scores and sexual identity, adjusting for covariates. Two separately gendered scales were developed, administered, and refined: BIAS-m (n=645), focusing on attitudes toward bisexual men; and BIAS-f (n=631), focusing on attitudes toward bisexual women. Across scales, sexual identity significantly predicted response variance. Lesbian/gay respondents had lower levels of bi-negative attitudes than their heterosexual counterparts (all p-values stereotypes and stigma may lead to dramatic disparities in depression, anxiety, stress, and other health outcomes among bisexual individuals in comparison to their heterosexual and homosexual counterparts. Our results yield valuable data for informing social awareness and intervention efforts that aim to decrease bi-negative attitudes within both straight and gay/lesbian communities, with the ultimate goal of alleviating health disparities among bisexual men and women.

The effect of proximity to hurricanes Katrina and Rita on subsequent hurricane outlook and optimistic bias.

Science.gov (United States)

Trumbo, Craig; Lueck, Michelle; Marlatt, Holly; Peek, Lori

2011-12-01

This study evaluated how individuals living on the Gulf Coast perceived hurricane risk after Hurricanes Katrina and Rita. It was hypothesized that hurricane outlook and optimistic bias for hurricane risk would be associated positively with distance from the Katrina-Rita landfall (more optimism at greater distance), controlling for historically based hurricane risk and county population density, demographics, individual hurricane experience, and dispositional optimism. Data were collected in January 2006 through a mail survey sent to 1,375 households in 41 counties on the coast (n = 824, 60% response). The analysis used hierarchal regression to test hypotheses. Hurricane history and population density had no effect on outlook; individuals who were male, older, and with higher household incomes were associated with lower risk perception; individual hurricane experience and personal impacts from Katrina and Rita predicted greater risk perception; greater dispositional optimism predicted more optimistic outlook; distance had a small effect but predicted less optimistic outlook at greater distance (model R(2) = 0.21). The model for optimistic bias had fewer effects: age and community tenure were significant; dispositional optimism had a positive effect on optimistic bias; distance variables were not significant (model R(2) = 0.05). The study shows that an existing measure of hurricane outlook has utility, hurricane outlook appears to be a unique concept from hurricane optimistic bias, and proximity has at most small effects. Future extension of this research will include improved conceptualization and measurement of hurricane risk perception and will bring to focus several concepts involving risk communication. © 2011 Society for Risk Analysis.

Ethnic bias and clinical decision-making among New Zealand medical students: an observational study.

Science.gov (United States)

Harris, Ricci; Cormack, Donna; Stanley, James; Curtis, Elana; Jones, Rhys; Lacey, Cameron

2018-01-23

Health professional racial/ethnic bias may impact on clinical decision-making and contribute to subsequent ethnic health inequities. However, limited research has been undertaken among medical students. This paper presents findings from the Bias and Decision-Making in Medicine (BDMM) study, which sought to examine ethnic bias (Māori (indigenous peoples) compared with New Zealand European) among medical students and associations with clinical decision-making. All final year New Zealand (NZ) medical students in 2014 and 2015 (n = 888) were invited to participate in a cross-sectional online study. Key components included: two chronic disease vignettes (cardiovascular disease (CVD) and depression) with randomized patient ethnicity (Māori or NZ European) and questions on patient management; implicit bias measures (an ethnicity preference Implicit Association Test (IAT) and an ethnicity and compliant patient IAT); and, explicit ethnic bias questions. Associations between ethnic bias and clinical decision-making responses to vignettes were tested using linear regression. Three hundred and two students participated (34% response rate). Implicit and explicit ethnic bias favoring NZ Europeans was apparent among medical students. In the CVD vignette, no significant differences in clinical decision-making by patient ethnicity were observed. There were also no differential associations by patient ethnicity between any measures of ethnic bias (implicit or explicit) and patient management responses in the CVD vignette. In the depression vignette, some differences in the ranking of recommended treatment options were observed by patient ethnicity and explicit preference for NZ Europeans was associated with increased reporting that NZ European patients would benefit from treatment but not Māori (slope difference 0.34, 95% CI 0.08, 0.60; p = 0.011), although this was the only significant finding in these analyses. NZ medical students demonstrated ethnic bias, although

The effect of a monetary incentive for administrative assistants on the survey response rate: a randomized controlled trial

Directory of Open Access Journals (Sweden)

Arnav Agarwal

2016-08-01

Full Text Available Abstract Background There is sufficient evidence that monetary incentives are effective in increasing survey response rates in the general population as well as with physicians. The objective of this study was to assess the impact of a monetary incentive intended for administrative assistants on the survey response rate of physicians in leadership positions. Methods This was an ancillary study to a national survey of chairs of academic Departments of Medicine in the United States about measuring faculty productivity. We randomized survey participants to receive or not receive a $5 gift card enclosed in the survey package. The cover letter explained that the gift card was intended for the administrative assistants as a “thank you for their time.” We compared the response rates between the 2 study arms using the Chi-square test. Results Out of 152 participants to whom survey packages were mailed to, a total of 78 responses were received (51 % response rate. The response rates were 59 % in the incentive arm and 46 % in the no incentive arm. The relative effect of the incentive compared to no monetary incentive was borderline statistically significant (relative risk (RR = 1.36, 95 % confidence interval (CI 0.99 to 1.87; p = 0.055. Conclusion Monetary incentives intended for administrative assistants likely increase the response rate of physicians in leadership positions.

Using experts’ consensus (the Delphi method) to evaluate weighting techniques in web surveys not based on probability schemes

NARCIS (Netherlands)

Toepoel, V.; Emerson, Hannah

2017-01-01

Weighting techniques in web surveys based on no probability schemes are devised to correct biases due to self-selection, undercoverage, and nonresponse. In an interactive panel, 38 survey experts addressed weighting techniques and auxiliary variables in web surveys. Most of them corrected all biases

HMO marketing and selection bias: are TEFRA HMOs skimming?

Science.gov (United States)

Lichtenstein, R; Thomas, J W; Watkins, B; Puto, C; Lepkowski, J; Adams-Watson, J; Simone, B; Vest, D

1992-04-01

The research evidence indicates that health maintenance organizations (HMOs) participating in the Tax Equity and Fiscal Responsibility Act of 1982 (TEFRA) At-Risk Program tend to experience favorable selection. Although favorable selection might result from patient decisions, a common conjecture is that it can be induced by HMOs through their marketing activities. The purpose of this study is to examine the relationship between HMO marketing strategies and selection bias in TEFRA At-Risk HMOs. A purposive sample of 22 HMOs that were actively marketing their TEFRA programs was selected and data on organizational characteristics, market area characteristics, and HMO marketing decisions were collected. To measure selection bias in these HMOs, the functional health status of approximately 300 enrollees in each HMO was compared to that of 300 non-enrolling beneficiaries in the same area. Three dependent variables, reflecting selection bias at the mean, the low health tail, and the high health tail of the health status distribution were created. Weighted least squares regressions were then used to identify relationships between marketing elements and selection bias. Subject to the statistical limitations of the study, our conclusion is that it is doubtful that HMO marketing decisions are responsible for the prevalence of favorable selection in HMO enrollment. It also appears unlikely that HMOs were differentially targeting healthy and unhealthy segments of the Medicare market.

Transition-transversion bias is not universal: a counter example from grasshopper pseudogenes.

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Irene Keller

2007-02-01

Full Text Available Comparisons of the DNA sequences of metazoa show an excess of transitional over transversional substitutions. Part of this bias is due to the relatively high rate of mutation of methylated cytosines to thymine. Postmutation processes also introduce a bias, particularly selection for codon-usage bias in coding regions. It is generally assumed, however, that there is a universal bias in favour of transitions over transversions, possibly as a result of the underlying chemistry of mutation. Surprisingly, this underlying trend has been evaluated only in two types of metazoan, namely Drosophila and the Mammalia. Here, we investigate a third group, and find no such bias. We characterize the point substitution spectrum in Podisma pedestris, a grasshopper species with a very large genome. The accumulation of mutations was surveyed in two pseudogene families, nuclear mitochondrial and ribosomal DNA sequences. The cytosine-guanine (CpG dinucleotides exhibit the high transition frequencies expected of methylated sites. The transition rate at other cytosine residues is significantly lower. After accounting for this methylation effect, there is no significant difference between transition and transversion rates. These results contrast with reports from other taxa and lead us to reject the hypothesis of a universal transition/transversion bias. Instead we suggest fundamental interspecific differences in point substitution processes.

Personality Traits and Susceptibility to Behavioral Biases among a Sample of Polish Stock Market Investors

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Rzeszutek Marcin

2015-09-01

Full Text Available The aim of this paper is to investigate whether susceptibility to selected behavioral biases (overconfidence, mental accounting and sunk-cost fallacy is correlated with the Eysenck’s [1978] personality traits (impulsivity, venturesomeness, and empathy. This study was conducted on a sample of 90 retail investors frequently investing on the Warsaw Stock Exchange. Participants filled out a survey made up of two parts: 1 three situational exercises, which assessed susceptibility to behavioral biases and 2 an Impulsiveness Questionnaire, which measures impulsivity, venturesomeness, and empathy. The results demonstrated the relationship between venturesomeness and susceptibility to all behavioral biases explored in this study. We find that higher level of venturesomeness was linked with a lower probability of all behavioral biases included in this study.

Regional Brain Responses Are Biased Toward Infant Facial Expressions Compared to Adult Facial Expressions in Nulliparous Women.

Science.gov (United States)

Li, Bingbing; Cheng, Gang; Zhang, Dajun; Wei, Dongtao; Qiao, Lei; Wang, Xiangpeng; Che, Xianwei

2016-01-01

Recent neuroimaging studies suggest that neutral infant faces compared to neutral adult faces elicit greater activity in brain areas associated with face processing, attention, empathic response, reward, and movement. However, whether infant facial expressions evoke larger brain responses than adult facial expressions remains unclear. Here, we performed event-related functional magnetic resonance imaging in nulliparous women while they were presented with images of matched unfamiliar infant and adult facial expressions (happy, neutral, and uncomfortable/sad) in a pseudo-randomized order. We found that the bilateral fusiform and right lingual gyrus were overall more activated during the presentation of infant facial expressions compared to adult facial expressions. Uncomfortable infant faces compared to sad adult faces evoked greater activation in the bilateral fusiform gyrus, precentral gyrus, postcentral gyrus, posterior cingulate cortex-thalamus, and precuneus. Neutral infant faces activated larger brain responses in the left fusiform gyrus compared to neutral adult faces. Happy infant faces compared to happy adult faces elicited larger responses in areas of the brain associated with emotion and reward processing using a more liberal threshold of p facial expressions compared to adult facial expressions among nulliparous women, and this bias may be modulated by individual differences in Interest-In-Infants and perspective taking ability.

Improving low power and shutdown PSA methods and data to permit better risk comparison and trade-off decision-making. Volume 1: summary of COOPRA and WGRISK surveys; Volume 2: responses to the WGRISK survey; Volume 3: responses to the COOPRA survey

International Nuclear Information System (INIS)

2005-01-01

The COOPRA LPSD working group is charged with the responsibility to assess their Member country's plant operations at Low Power and Shutdown (LPSD) conditions. The sharing of information is expected to provide each of the Member country the means from which to render informed regulatory decisions for the benefit of public health and safety. Each organization had developed a questionnaire to gather information from Member countries on LPSD PSAs experiences. The responses cover a broad spectrum of LPSD PSA topics, and identifies work for improving risk-informed trade-off decisions, using PSA techniques, between LPSD and full power operational states. Each organization recognized potential benefit for improving the state-of-the-art by combining the wealth of experiences from the questionnaire responses into a common report. This report provides a summary of the current LPSD PSAs in Member countries, covering the elements which make up the PSAs. This report identifies the uses of the LPSD PSAs, summarizes current approaches, aspects, and good practices, identifies and defines differences between methods and data in full power and LPSD PSAs, and identifies guidance, methods, data, and basic research needs to address the differences. The responses to the questionnaires are provided in the Appendixes. The information contained in this report was gathered from two surveys, one by COOPRA and the other by WGRisk, which were performed over several years. Volume 2 of this report contains the responses from the CSNI / WGRisk Survey; Volume 3 contains the responses from the COOPRA Survey

The skewed weak lensing likelihood: why biases arise, despite data and theory being sound.

Science.gov (United States)

Sellentin, Elena; Heymans, Catherine; Harnois-Déraps, Joachim

2018-04-01

We derive the essentials of the skewed weak lensing likelihood via a simple Hierarchical Forward Model. Our likelihood passes four objective and cosmology-independent tests which a standard Gaussian likelihood fails. We demonstrate that sound weak lensing data are naturally biased low, since they are drawn from a skewed distribution. This occurs already in the framework of ΛCDM. Mathematically, the biases arise because noisy two-point functions follow skewed distributions. This form of bias is already known from CMB analyses, where the low multipoles have asymmetric error bars. Weak lensing is more strongly affected by this asymmetry as galaxies form a discrete set of shear tracer particles, in contrast to a smooth shear field. We demonstrate that the biases can be up to 30% of the standard deviation per data point, dependent on the properties of the weak lensing survey and the employed filter function. Our likelihood provides a versatile framework with which to address this bias in future weak lensing analyses.

The ‘male escape hypothesis’: sex-biased metamorphosis in response to climatic drivers in a facultatively paedomorphic amphibian

Science.gov (United States)

Mathiron, Anthony G. E.; Lena, Jean-Paul; Baouch, Sarah

2017-01-01

Paedomorphosis is a major evolutionary process that bypasses metamorphosis and allows reproduction in larvae. In newts and salamanders, it can be facultative with paedomorphs retaining gills and metamorphs dispersing. The evolution of these developmental processes is thought to have been driven by the costs and benefits of inhabiting aquatic versus terrestrial habitats. In this context, we aimed at testing the hypothesis that climatic drivers affect phenotypic transition and the difference across sexes because sex-ratio is biased in natural populations. Through a replicated laboratory experiment, we showed that paedomorphic palmate newts (Lissotriton helveticus) metamorphosed at a higher frequency when water availability decreased and metamorphosed earlier when temperature increased in these conditions. All responses were sex-biased, and males were more prone to change phenotype than females. Our work shows how climatic variables can affect facultative paedomorphosis and support theoretical models predicting life on land instead of in water. Moreover, because males metamorphose and leave water more often and earlier than females, these results, for the first time, give an experimental explanation for the rarity of male paedomorphosis (the ‘male escape hypothesis’) and suggest the importance of sex in the evolution of paedomorphosis versus metamorphosis. PMID:28424346

Radiation effect of doping and bias conditions on NPN bipolar junction transistors

International Nuclear Information System (INIS)

Xi Shanbin; Wang Yiyuan; Xu Fayue; Zhou Dong; Li Ming; Wang Fei; Wang Zhikuan; Yang Yonghui; Lu Wu

2011-01-01

In this paper,we investigate 60 Co γ-ray irradiation effects and annealing behaviors of NPN bipolar junction transistors of the same manufacturing technology but different doping concentrations. The transistors of different doping concentrations differ in responses of the radiation effect. More degradation was observed with the transistors of low concentration-doped NPN transistors than the high concentration-doped NPN transistors. The results also demonstrate that reverse-biased transistors are more sensitive to radiation than the forward-biased ones. Mechanisms of the radiation responses are analyzed. (authors)

Journal bias or author bias?

Science.gov (United States)

Harris, Ian

2016-01-01

I read with interest the comment by Mark Wilson in the Indian Journal of Medical Ethics regarding bias and conflicts of interest in medical journals. Wilson targets one journal (the New England Journal of Medicine: NEJM) and one particular "scandal" to make his point that journals' decisions on publication are biased by commercial conflicts of interest (CoIs). It is interesting that he chooses the NEJM which, by his own admission, had one of the strictest CoI policies and had published widely on this topic. The feeling is that if the NEJM can be guilty, they can all be guilty.

Estimating disease prevalence from two-phase surveys with non-response at the second phase

Science.gov (United States)

Gao, Sujuan; Hui, Siu L.; Hall, Kathleen S.; Hendrie, Hugh C.

2010-01-01

SUMMARY In this paper we compare several methods for estimating population disease prevalence from data collected by two-phase sampling when there is non-response at the second phase. The traditional weighting type estimator requires the missing completely at random assumption and may yield biased estimates if the assumption does not hold. We review two approaches and propose one new approach to adjust for non-response assuming that the non-response depends on a set of covariates collected at the first phase: an adjusted weighting type estimator using estimated response probability from a response model; a modelling type estimator using predicted disease probability from a disease model; and a regression type estimator combining the adjusted weighting type estimator and the modelling type estimator. These estimators are illustrated using data from an Alzheimer’s disease study in two populations. Simulation results are presented to investigate the performances of the proposed estimators under various situations. PMID:10931514

Inferred fish behavior its implications for hydroacoustic surveys in nearshore habitats

Science.gov (United States)

DuFour, Mark R.; Mayer, Christine M.; Qian, Song S.; Vandergoot, Christopher; Kraus, Richard T.; Kocovsky, Patrick; Warner, David M.

2018-01-01

Population availability and vessel avoidance effects on hydroacoustic abundance estimates may be scale dependent; therefore, it is important to evaluate these biases across systems. We performed an inter-ship comparison survey to determine the effect of vessel size, day-night period, depth, and environmental gradients on walleye (Sander vitreus) density estimates in Lake Erie, an intermediate-scaled system. Consistent near-bottom depth distributions coupled with horizontal fish movements relative to vessel paths indicated avoidance behavior contributed to higher walleye densities from smaller vessels in shallow water (i.e., <15 m), although the difference decreased with increasing depth. Diel bank migrations in response to seasonally varying onshore-to-offshore environmental gradients likely contributed to day-night differences in densities between sampling locations and seasons. Spatial and unexplained variation accounted for a high proportion of total variation; however, increasing sampling intensity can mitigate effects on precision. Therefore, researchers should minimize systematic avoidance and availability related biases (i.e., vessel and day-night period) to improve population abundance estimates. Quantifying availability and avoidance behavior effects and partitioning sources of variation provides informed flexibility for designing future hydroacoustic surveys in shallow-water nearshore environments.

Masking in reports of "most serious" events: bias in estimators of sports injury incidence in Canadian children

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A. Gupta

2016-08-01

Full Text Available Introduction: Surveys that collect information on injuries often focus on the single "most serious" event to help limit recall error and reduce survey length. However, this can mask less serious injuries and result in biased incidence estimates for specific injury subcategories. Methods: Data from the 2002 Health Behaviour in School-aged Children (HBSC survey and from the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP were used to compare estimates of sports injury incidence in Canadian children. Results: HBSC data indicate that 6.7% of children report sustaining a sports injury that required an emergency department (ED visit. However, details were only collected on a child's "most serious" injury, so children who had multiple injuries requiring an ED visit may have had sports injuries that went unreported. The rate of 6.7% can be seen to be an underestimate by as much as 4.3%. Corresponding CHIRPP surveillance data indicate an incidence of 9.9%. Potential masking bias is also highlighted in our analysis of injuries attended by other health care providers. Conclusion: The "one most serious injury" line of questioning induces potentially substantial masking bias in the estimation of sports injury incidence, which limits researchers' ability to quantify the burden of sports injury. Longer survey recall periods naturally lead to greater masking. The design of future surveys should take these issues into account. In order to accurately inform policy decisions and the direction of future research, researchers must be aware of these limitations.

Measuring the difference in mean willingness to pay when dichotomous choice contingent valuation responses are not independent

Science.gov (United States)

Gregory L. Poe; Michael P. Welsh; Patricia A. Champ

1997-01-01

Dichotomous choice contingent valuation surveys frequently elicit multiple values in a single questionnaire. If individual responses are correlated across scenarios, the standard approach of estimating willingness to pay (WTP) functions independently for each scenario may result in biased estimates of the significance of the difference in mean WTP values. This paper...

Optimistic bias, advertising skepticism, and consumer intentions for seeking information about the health risks of prescription medicine.

Science.gov (United States)

Park, Jin Seong; Ahn, Ho-Young Anthony; Haley, Eric John

2017-01-01

Based on a survey of prescription drug users (N = 408), this study revealed that: (a) the frequency of consumers' personal experience of prescription medicine adverse reactions negatively related to the extent of their optimistic bias about the chances of such events, (b) consumers' perceived personal control over adverse reactions positively related to optimistic bias, and (c) optimistic bias related more negatively to intentions to seek risk information when consumer skepticism toward direct-to-consumer advertising was high. When skepticism was low to average, optimistic bias did not inhibit such intentions. Implications and recommendations for the practice of direct-to-consumer advertising are provided.

Survey of state and tribal emergency response capabilities for radiological transportation incidents

Energy Technology Data Exchange (ETDEWEB)

Vilardo, F J; Mitter, E L; Palmer, J A; Briggs, H C; Fesenmaier, J [Indiana Univ., Bloomington, IN (USA). School of Public and Environmental Affairs

1990-05-01

This publication is the final report of a project to survey the fifty states, the District of Columbia, Puerto Rico, and selected Indian Tribal jurisdictions to ascertain their emergency-preparedness planning and capabilities for responding to transportation incidents involving radioactive materials. The survey was conducted to provide the Nuclear Regulatory Commission and other federal agencies with information concerning the current level of emergency-response preparedness of the states and selected tribes and an assessment of the changes that have occurred since 1980. There have been no major changes in the states' emergency-response planning strategies and field tactics. The changes noted included an increased availability of dedicated emergency-response vehicles, wider availability of specialized radiation-detection instruments, and higher proportions of police and fire personnel with training in the handling of suspected radiation threats. Most Indian tribes have no capability to evaluate suspected radiation threats and have no formal relations with emergency-response personnel in adjacent states. For the nation as a whole, the incidence of suspected radiation threats declined substantially from 1980 to 1988. 58 tabs.

[Immortal time bias in pharmacoepidemiological studies: definition, solutions and examples].

Science.gov (United States)

Faillie, Jean-Luc; Suissa, Samy

2015-01-01

Among the observational studies of drug effects in chronic diseases, many of them have found effects that were exaggerated or wrong. Among bias responsible for these errors, the immortal time bias, concerning the definition of exposure and exposure periods, is relevantly important as it usually tends to wrongly attribute a significant benefit to the study drug (or exaggerate a real benefit). In this article, we define the mechanism of immortal time bias, we present possible solutions and illustrate its consequences through examples of pharmacoepidemiological studies of drug effects. © 2014 Société Française de Pharmacologie et de Thérapeutique.

A survey of optometry leadership: participation in disaster response.

Science.gov (United States)

Psoter, Walter J; Glotzer, David L; Weiserbs, Kera Fay; Baek, Linda S; Karloopia, Rajiv

2012-01-01

A study was completed to assess the academic and state-level professional optometry leadership views regarding optometry professionals as surge responders in the event of a catastrophic event. A cross-sectional survey was conducted using a 21-question, self-administered, structured questionnaire. All U.S. optometry school deans and state optometric association presidents were mailed a questionnaire and instructions to return it by mail on completion; 2 repeated mailings were made. Descriptive statistics were produced and differences between deans and association presidents were tested by Fisher exact test. The questionnaire response rate was 50% (25 returned/50 sent) for the state association presidents and 65% (11/17) for the deans. There were no statistically significant differences between the leadership groups for any survey questions. All agreed that optometrists have the skills, are ethically obligated to help, and that optometrists should receive additional training for participation in disaster response. There was general agreement that optometrists should provide first-aid, obtain medical histories, triage, maintain infection control, manage a point of distribution, prescribe medications, and counsel the "worried well." Starting intravenous lines, interpreting radiographs, and suturing were less favorably supported. There was some response variability between the 2 leadership groups regarding potential sources for training. The overall opinion of optometry professional leadership is that with additional training, optometrists can and should provide an important reserve pool of catastrophic event responders. Copyright © 2011 American Optometric Association. Published by Elsevier Inc. All rights reserved.

Dual Systems for Spatial Updating in Immediate and Retrieved Environments: Evidence from Bias Analysis.

Science.gov (United States)

Liu, Chuanjun; Xiao, Chengli

2018-01-01

The spatial updating and memory systems are employed during updating in both the immediate and retrieved environments. However, these dual systems seem to work differently, as the difference of pointing latency and absolute error between the two systems vary across environments. To verify this issue, the present study employed the bias analysis of signed errors based on the hypothesis that the transformed representation will bias toward the original one. Participants learned a spatial layout and then either stayed in the learning location or were transferred to a neighboring room directly or after being disoriented. After that, they performed spatial judgments from perspectives aligned with the learning direction, aligned with the direction they faced during the test, or a novel direction misaligned with the two above-mentioned directions. The patterns of signed error bias were consistent across environments. Responses for memory aligned perspectives were unbiased, whereas responses for sensorimotor aligned perspectives were biased away from the memory aligned perspective, and responses for misaligned perspectives were biased toward sensorimotor aligned perspectives. These findings indicate that the spatial updating system is consistently independent of the spatial memory system regardless of the environments, but the updating system becomes less accessible as the environment changes from immediate to a retrieved one.

Dual Systems for Spatial Updating in Immediate and Retrieved Environments: Evidence from Bias Analysis

Directory of Open Access Journals (Sweden)

Chuanjun Liu

2018-02-01

Full Text Available The spatial updating and memory systems are employed during updating in both the immediate and retrieved environments. However, these dual systems seem to work differently, as the difference of pointing latency and absolute error between the two systems vary across environments. To verify this issue, the present study employed the bias analysis of signed errors based on the hypothesis that the transformed representation will bias toward the original one. Participants learned a spatial layout and then either stayed in the learning location or were transferred to a neighboring room directly or after being disoriented. After that, they performed spatial judgments from perspectives aligned with the learning direction, aligned with the direction they faced during the test, or a novel direction misaligned with the two above-mentioned directions. The patterns of signed error bias were consistent across environments. Responses for memory aligned perspectives were unbiased, whereas responses for sensorimotor aligned perspectives were biased away from the memory aligned perspective, and responses for misaligned perspectives were biased toward sensorimotor aligned perspectives. These findings indicate that the spatial updating system is consistently independent of the spatial memory system regardless of the environments, but the updating system becomes less accessible as the environment changes from immediate to a retrieved one.

The Bias in Favor of Venture Capital Finance in U.S. Entrepreneurial Education: At the Expense of Trade Credit

Science.gov (United States)

Clement, Thomas; LeMire, Steven; Silvernagel, Craig

2015-01-01

The authors examine whether U.S. college-level entrepreneurship education demonstrates a bias favoring venture capital (VC) financing while marginalizing trade credit financing, and the resulting impact on entrepreneurship students. A sample of U.S. business textbooks and survey data from entrepreneurship students reveals a significant bias toward…

Does an offer for a free on-line continuing medical education (CME) activity increase physician survey response rate? A randomized trial.

Science.gov (United States)

Viera, Anthony J; Edwards, Teresa

2012-03-07

Achieving a high response rate in a physician survey is challenging. Monetary incentives increase response rates but obviously add cost to a survey project. We wondered whether an offer of a free continuing medical education (CME) activity would be effective in improving survey response rate. As part of a survey of a national sample of physicians, we randomized half to an offer for a free on-line CME activity upon completion of a web-based survey and the other half to no such offer. We compared response rates between the groups. A total of 1214 out of 8477 potentially eligible physicians responded to our survey, for an overall response rate of 14.3%. The response rate among the control group (no offer of CME credit) was 16.6%, while among those offered the CME opportunity, the response rate was 12.0% (p offer for a free on-line CME activity did not improve physician survey response rate. On the contrary, the offer for a free CME activity actually appeared to worsen the response rate. © 2011 Viera et al; licensee BioMed Central Ltd.

Selection bias in Web surveys and the use of propensity scores

NARCIS (Netherlands)

Schonlau, M.; van Soest, A.H.O.; Kapteyn, A.; Couper, M.

2009-01-01

Web surveys are a popular survey mode, but the subpopulation with Internet access may not represent the population of interest. The authors investigate whether adjusting using weights or matching on a small set of variables makes the distributions of target variables representative of the

Survey of system responsibility in the Nordic countries. Final report

International Nuclear Information System (INIS)

2005-02-01

In September 2004 the Nordic Council of Ministers asked Nordel to perform some tasks and present the results to the Council on 1 March 2005. One of the tasks is to survey how system responsibility is defined and executed in the different Nordic countries. According to the Nordic Council of Ministers, the survey shall illuminate similarities and differences between the countries and assess the reasons for the differences. Nordel is asked to present a joint view system responsibility in the Nordic countries. Among other things, the responsibility for the system operators and the participants in the market shall be defined. The definition shall also include the distribution of costs between costs for network business and costs for business in competition. This shall be done in a way that creates a common platform for the further harmonisation work and continuous positive development of the Nordic electricity market. It is also important to identify the need for changes in e.g. legislation and guidelines in the different countries as a consequence of an implementation of a common definition in the Nordic countries. Areas to be included in the task are among others, balance settlement, security of supply, congestion management and system services. (BA)

Prospective evaluation of direct approach with a tablet device as a strategy to enhance survey study participant response rate

Directory of Open Access Journals (Sweden)

Parker Melissa J

2012-10-01

Full Text Available Abstract Background Investigators conduct survey studies for a variety of reasons. Poor participant response rates are common, however, and may limit the generalizability and utility of results. The objective of this study was to determine whether direct approach with a tablet device enhances survey study participant response rate and to assess participants’ experiences with this mode of survey administration. Findings An interventional study nested within a single center survey study was conducted at McMaster Children’s Hospital. The primary outcome was the ability to achieve of a survey study response rate of 70% or greater. Eligible participants received 3 email invitations (Week 0, 2, 4 to complete a web-based (Survey Monkey survey. The study protocol included plans for a two-week follow-up phase (Phase 2 where non-responders were approached by a research assistant and invited to complete an iPad-based version of the survey. The Phase 1 response rate was 48.7% (56/115. Phase 2 effectively recruited reluctant responders, increasing the overall response rate to 72.2% (83/115. On a 7-point Likert scale, reluctant responders highly rated their enjoyment (mean 6.0, sd 0.83 [95% CI: 5.7-6.3] and ease of use (mean 6.7, sd 0.47 [95% CI: 6.5-6.9] completing the survey using the iPad. Reasons endorsed for Phase 2 participation included: direct approach (81%, immediate survey access (62%, and the novelty of completing a tablet-based survey (54%. Most reluctant responders (89% indicated that a tablet-based survey is their preferred method of survey completion. Conclusions Use of a tablet-based version of the survey was effective in recruiting reluctant responders and this group reported positive experiences with this mode of survey administration.

Investment, managerial capacity, and bias in public health preparedness.

Science.gov (United States)

Langabeer, James R; DelliFraine, Jami L; Tyson, Sandra; Emert, Jamie M; Herbold, John

2009-01-01

Nearly $7 billion has been invested through national cooperative funding since 2002 to strengthen state and local response capacity. Yet, very little outcome evidence exists to analyze funding effectiveness. The objective of this research is to analyze the relationship between investment (funding) and capacity (readiness) for public health preparedness (PHP). The aim of the authors is to use a management framework to evaluate capacity, and to explore the "immediacy bias" impact on investment stability. This study employs a longitudinal study design, incorporating survey research of the entire population of 68 health departments in the state of Texas. The authors assessed the investment-capacity relationship through several statistical methods. The authors created a structural measure of managerial capacity through principal components analysis, factorizing 10 independent variables and augment this with a perceived readiness level reported from PHP managers. The authors then employ analysis of variance, correlation analyses, and other descriptive statistics. There has been a 539 percent coefficient of variation in funding at the local level between the years 2004 and 2008, and a 63 percent reduction in total resources since the peak of funding, using paired sample data. Results suggest that investment is positively associated with readiness and managerial capacity in local health departments. The authors also find that investment was related to greater community collaboration, higher adoption of Incident Command System (ICS) structure, and more frequent operational drills and exercises. Greater investment is associated with higher levels of capacity and readiness. The authors conclude from this that investment should be stabilized and continued, and not be influenced by historical cognitive biases.

How trait anxiety, interpretation bias and memory affect acquired fear in children learning about new animals.

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Field, Zoë C; Field, Andy P

2013-06-01

Cognitive models of vulnerability to anxiety propose that information processing biases such as interpretation bias play a part in the etiology and maintenance of anxiety disorders. However, at present little is known about the role of memory in information processing accounts of child anxiety. The current study investigates the relationships between interpretation biases, memory and fear responses when learning about new stimuli. Children (aged 8-11 years) were presented with ambiguous information regarding a novel animal, and their fear, interpretation bias, and memory for the information was measured. The main findings were: (1) trait anxiety and interpretation bias significantly predicted acquired fear; (2) interpretation bias did not significantly mediate the relationship between trait anxiety and acquired fear; (3) interpretation bias appeared to be a more important predictor of acquired fear than trait anxiety per se; and (4) the relationship between interpretation bias and acquired fear was not mediated by the number of negative memories but was mediated by the number of positive and false-positive memories. The findings suggest that information processing models of child anxiety need to explain the role of positive memory in the formation of fear responses.

OSSOS. VI. Striking Biases in the Detection of Large Semimajor Axis Trans-Neptunian Objects

Science.gov (United States)

Shankman, Cory; Kavelaars, J. J.; Bannister, Michele T.; Gladman, Brett J.; Lawler, Samantha M.; Chen, Ying-Tung; Jakubik, Marian; Kaib, Nathan; Alexandersen, Mike; Gwyn, Stephen D. J.; Petit, Jean-Marc; Volk, Kathryn

2017-08-01

The accumulating but small set of large semimajor axis trans-Neptunian objects (TNOs) shows an apparent clustering in the orientations of their orbits. This clustering must either be representative of the intrinsic distribution of these TNOs, or else have arisen as a result of observation biases and/or statistically expected variations for such a small set of detected objects. The clustered TNOs were detected across different and independent surveys, which has led to claims that the detections are therefore free of observational bias. This apparent clustering has led to the so-called “Planet 9” hypothesis that a super-Earth currently resides in the distant solar system and causes this clustering. The Outer Solar System Origins Survey (OSSOS) is a large program that ran on the Canada–France–Hawaii Telescope from 2013 to 2017, discovering more than 800 new TNOs. One of the primary design goals of OSSOS was the careful determination of observational biases that would manifest within the detected sample. We demonstrate the striking and non-intuitive biases that exist for the detection of TNOs with large semimajor axes. The eight large semimajor axis OSSOS detections are an independent data set, of comparable size to the conglomerate samples used in previous studies. We conclude that the orbital distribution of the OSSOS sample is consistent with being detected from a uniform underlying angular distribution.

Context effects and observer bias--implications for forensic odontology.

Science.gov (United States)

Page, Mark; Taylor, Jane; Blenkin, Matt

2012-01-01

Psychologists have long recognized the effects of contextual and extraneous information on decision making. Such information renders the subject susceptible to both motivational and cognitive bias; yet, it is difficult to assess the extent to which these influence forensic odontologists opinions as there have been no studies to date on this subject. This article explores the various types of contextual effects and biasing influences that potentially impact on the analysis of bitemarks in forensic odontology. It appears that the current practice of bitemark analysis is rich in sources of potentially biasing influences. In addition to the fundamental recognition that some form of bias is likely to exist, ways in which these should be minimized include: separation of the collection and analysis phases; limiting the amount of contextual information available to the odontologist responsible for the analysis; and ensuring that evidence that is ambiguous or of poor quality is identified as such prior to analysis. © 2011 American Academy of Forensic Sciences.

Beyond assembly bias: exploring secondary halo biases for cluster-size haloes

Science.gov (United States)

Mao, Yao-Yuan; Zentner, Andrew R.; Wechsler, Risa H.

2018-03-01

Secondary halo bias, commonly known as `assembly bias', is the dependence of halo clustering on a halo property other than mass. This prediction of the Λ Cold Dark Matter cosmology is essential to modelling the galaxy distribution to high precision and interpreting clustering measurements. As the name suggests, different manifestations of secondary halo bias have been thought to originate from halo assembly histories. We show conclusively that this is incorrect for cluster-size haloes. We present an up-to-date summary of secondary halo biases of high-mass haloes due to various halo properties including concentration, spin, several proxies of assembly history, and subhalo properties. While concentration, spin, and the abundance and radial distribution of subhaloes exhibit significant secondary biases, properties that directly quantify halo assembly history do not. In fact, the entire assembly histories of haloes in pairs are nearly identical to those of isolated haloes. In general, a global correlation between two halo properties does not predict whether or not these two properties exhibit similar secondary biases. For example, assembly history and concentration (or subhalo abundance) are correlated for both paired and isolated haloes, but follow slightly different conditional distributions in these two cases. This results in a secondary halo bias due to concentration (or subhalo abundance), despite the lack of assembly bias in the strict sense for cluster-size haloes. Due to this complexity, caution must be exercised in using any one halo property as a proxy to study the secondary bias due to another property.

The Galileo Bias: A Naive Conceptual Belief That Influences People's Perceptions and Performance in a Ball-Dropping Task

Science.gov (United States)

Oberle, Crystal D.; McBeath, Michael K.; Madigan, Sean C.; Sugar, Thomas G.

2005-01-01

This research introduces a new naive physics belief, the Galileo bias, whereby people ignore air resistance and falsely believe that all objects fall at the same rate. Survey results revealed that this bias is held by many and is surprisingly strongest for those with formal physics instruction. In 2 experiments, 98 participants dropped ball pairs…

Immune markers of social cognitive bias in schizophrenia.

Science.gov (United States)

Dunne, Patrick W; Roberts, David L; Quinones, Marlon P; Velligan, Dawn I; Paredes, Madelaine; Walss-Bass, Consuelo

2017-05-01

Social cognition is impaired in schizophrenia, is relatively independent of purely neurocognitive domains such as attention and executive functioning, and may be the strongest predictor of functional outcome in this disease. Within a motivated reasoning framework, we tested the hypothesis that the anti-inflammatory Th2-associated cytokines, IL-10 and MDC, would be correlated with behavioral measures of social cognitive threat-detection bias (self-referential gaze detection bias and theory of mind (ToM) bias) in delusional versus non-delusional patients. We administered to schizophrenia patients with delusions (n=21), non-delusional patients (n=39) and controls (n=20) a social cognitive task designed to be sensitive to psychosocial stress response (the Waiting Room Task) and collected plasma levels of inflammatory markers using a bead-based flow immunoassay. Results partially supported our hypothesis. The anti-inflammatory cytokine IL-10 was associated with self-referential ToM bias in the delusional cohort as predicted, and not with non-delusional patients or healthy controls. This bias reflects a documented tendency of schizophrenia patients with delusions to excessively attribute hostile intentions to people in their environment. Since this cytokine correlated only with ToM bias and only in delusional patients, elevated levels of this cytokine in the blood may eventually serve as a useful biomarker distinguishing delusional patients from both non-delusional patients and healthy controls. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Reflexive intergroup bias in third-party punishment.

Science.gov (United States)

Yudkin, Daniel A; Rothmund, Tobias; Twardawski, Mathias; Thalla, Natasha; Van Bavel, Jay J

2016-11-01

Humans show a rare tendency to punish norm-violators who have not harmed them directly-a behavior known as third-party punishment. Research has found that third-party punishment is subject to intergroup bias, whereby people punish members of the out-group more severely than the in-group. Although the prevalence of this behavior is well-documented, the psychological processes underlying it remain largely unexplored. Some work suggests that it stems from people's inherent predisposition to form alliances with in-group members and aggress against out-group members. This implies that people will show reflexive intergroup bias in third-party punishment, favoring in-group over out-group members especially when their capacity for deliberation is impaired. Here we test this hypothesis directly, examining whether intergroup bias in third-party punishment emerges from reflexive, as opposed to deliberative, components of moral cognition. In 3 experiments, utilizing a simulated economic game, we varied participants' group relationship to a transgressor, measured or manipulated the extent to which they relied on reflexive or deliberative judgment, and observed people's punishment decisions. Across group-membership manipulations (American football teams, nationalities, and baseball teams) and 2 assessments of reflexive judgment (response time and cognitive load), reflexive judgment heightened intergroup bias, suggesting that such bias in punishment is inherent to human moral cognition. We discuss the implications of these studies for theories of punishment, cooperation, social behavior, and legal practice. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Pre-notification letter type and response rate to a postal survey among women who have recently given birth.

Science.gov (United States)

Todd, Angela L; Porter, Maree; Williamson, Jennifer L; Patterson, Jillian A; Roberts, Christine L

2015-12-01

Surveys are commonly used in health research to assess patient satisfaction with hospital care. Achieving an adequate response rate, in the face of declining trends over time, threatens the quality and reliability of survey results. This paper evaluates a strategy to increase the response rate in a postal satisfaction survey with women who had recently given birth. A sample of 2048 Australian women who had recently given birth at seven maternity units in New South Wales were invited to participate in a postal survey about their recent experiences with maternity care. The study design included a randomised controlled trial that tested two types of pre-notification letter (with or without the option of opting out of the survey). The study also explored the acceptability of a request for consent to link survey data with existing routinely collected health data (omitting the latter data items from the survey reduced survey length and participant burden). This consent was requested of all women. The survey had an overall response rate of 46% (913 completed surveys returned, total sample 1989). Women receiving the pre-notification letter with the option of opting out of the survey were more likely to actively decline to participate than women receiving the letter without this option, although the overall numbers of women declining were small (27 versus 12). Letter type was not significantly associated with the return of a completed survey. Among women who completed the survey, 97% gave consent to link their survey data with existing health data. The two types of pre-notification letters used in our study did not influence the survey response rate. However, seeking consent for record linkage was highly acceptable to women who completed the survey, and represents an important strategy to add to the arsenal for designing and implementing effective surveys. In addition to aspects of survey design, future research should explore how to more effectively influence personal

Choir of believers? Longitudinal evidence on public service motivation and survey participation

DEFF Research Database (Denmark)

Jacobsen, Christian Bøtcher; De Lorent Gad, Mette; Kjeldsen, Anne Mette

The most widely used method to study individuals’ public service motivation is surveys. The validity and inferential power of such studies may, however, be harmed by survey participation bias, if highly public service motivated individuals are overrepresented among respondents. This paper examines...... the methodological critique of survey participation bias raised against the public service motivation literature and examines whether public service motivation increases the propensity to respond to surveys. By tracking more than 3,000 public service providers’ participation in a three-wave panel survey, our...... analysis shows that public service motivation does have a positive effect on survey participation. This suggests that future studies should pay attention to the characteristics of respondents/non-respondents and consider weighting the sample....

Motivational mechanisms and outcome expectancies underlying the approach bias towards addictive substances

Directory of Open Access Journals (Sweden)

Poppy eWatson

2012-10-01

Full Text Available Human behavior can be paradoxical, in that actions can be initiated that are seemingly incongruent with an individual’s explicit desires. This is most commonly observed in drug addiction, where maladaptive behavior (i.e. drug seeking appears to be compulsive, continuing at great personal cost. Approach biases towards addictive substances have been correlated with actual drug-use in a number of studies, suggesting that this measure can, in some cases, index everyday maladaptive tendencies. At present it is unclear whether this bias to drug cues is a Pavlovian conditioned approach response, a habitual response, the result of a Pavlovian-instrumental transfer process or a goal-directed action in the sense that expectancy of the rewarding effects of drugs controls approach. We consider this question by combining the theoretical framework of associative learning with the available evidence from approach bias research. Although research investigating the relative contributions of these mechanisms to the approach bias is to date relatively limited, we review existing studies and also outline avenues for future research.

Motivational Mechanisms and Outcome Expectancies Underlying the Approach Bias toward Addictive Substances.

Science.gov (United States)

Watson, P; de Wit, S; Hommel, Bernhard; Wiers, R W

2012-01-01

Human behavior can be paradoxical, in that actions can be initiated that are seemingly incongruent with an individual's explicit desires. This is most commonly observed in drug addiction, where maladaptive behavior (i.e., drug seeking) appears to be compulsive, continuing at great personal cost. Approach biases toward addictive substances have been correlated with actual drug-use in a number of studies, suggesting that this measure can, in some cases, index everyday maladaptive tendencies. At present it is unclear whether this bias to drug cues is a Pavlovian conditioned approach response, a habitual response, the result of a Pavlovian-instrumental transfer process, or a goal-directed action in the sense that expectancy of the rewarding effects of drugs controls approach. We consider this question by combining the theoretical framework of associative learning with the available evidence from approach bias research. Although research investigating the relative contributions of these mechanisms to the approach bias is to date relatively limited, we review existing studies and also outline avenues for future research.

The SDT Model of Belief Bias: Complexity, Time, and Cognitive Ability Mediate the Effects of Believability

Science.gov (United States)

Trippas, Dries; Handley, Simon J.; Verde, Michael F.

2013-01-01

When people evaluate conclusions, they are often influenced by prior beliefs. Prevalent theories claim that "belief bias" affects the quality of syllogistic reasoning. However, recent work by Dube, Rotello, and Heit (2010) has suggested that belief bias may be a simple response bias. In Experiment 1, receiver operating characteristic…

Individual differences in bodily freezing predict emotional biases in decision making

NARCIS (Netherlands)

Ly, V.; Huys, Q.; Stins, J.F.; Roelofs, K.; Cools, R.

2014-01-01

Instrumental decision making has long been argued to be vulnerable to emotional responses. Literature on multiple decision making systems suggests that this emotional biasing might reflect effects of a system that regulates innately specified, evolutionarily preprogrammed responses. To test this

Peak-locking centroid bias in Shack-Hartmann wavefront sensing

Science.gov (United States)

Anugu, Narsireddy; Garcia, Paulo J. V.; Correia, Carlos M.

2018-05-01

Shack-Hartmann wavefront sensing relies on accurate spot centre measurement. Several algorithms were developed with this aim, mostly focused on precision, i.e. minimizing random errors. In the solar and extended scene community, the importance of the accuracy (bias error due to peak-locking, quantization, or sampling) of the centroid determination was identified and solutions proposed. But these solutions only allow partial bias corrections. To date, no systematic study of the bias error was conducted. This article bridges the gap by quantifying the bias error for different correlation peak-finding algorithms and types of sub-aperture images and by proposing a practical solution to minimize its effects. Four classes of sub-aperture images (point source, elongated laser guide star, crowded field, and solar extended scene) together with five types of peak-finding algorithms (1D parabola, the centre of gravity, Gaussian, 2D quadratic polynomial, and pyramid) are considered, in a variety of signal-to-noise conditions. The best performing peak-finding algorithm depends on the sub-aperture image type, but none is satisfactory to both bias and random errors. A practical solution is proposed that relies on the antisymmetric response of the bias to the sub-pixel position of the true centre. The solution decreases the bias by a factor of ˜7 to values of ≲ 0.02 pix. The computational cost is typically twice of current cross-correlation algorithms.

ACTIVE LEARNING TO OVERCOME SAMPLE SELECTION BIAS: APPLICATION TO PHOTOMETRIC VARIABLE STAR CLASSIFICATION

Energy Technology Data Exchange (ETDEWEB)

Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Berian James, J. [Astronomy Department, University of California, Berkeley, CA 94720-7450 (United States); Brink, Henrik [Dark Cosmology Centre, Juliane Maries Vej 30, 2100 Copenhagen O (Denmark); Long, James P.; Rice, John, E-mail: jwrichar@stat.berkeley.edu [Statistics Department, University of California, Berkeley, CA 94720-7450 (United States)

2012-01-10

Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL-where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up-is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

ACTIVE LEARNING TO OVERCOME SAMPLE SELECTION BIAS: APPLICATION TO PHOTOMETRIC VARIABLE STAR CLASSIFICATION

International Nuclear Information System (INIS)

Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Berian James, J.; Brink, Henrik; Long, James P.; Rice, John

2012-01-01

Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL—where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up—is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

Active Learning to Overcome Sample Selection Bias: Application to Photometric Variable Star Classification

Science.gov (United States)

Richards, Joseph W.; Starr, Dan L.; Brink, Henrik; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; James, J. Berian; Long, James P.; Rice, John

2012-01-01

Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL—where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up—is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

Specificity of interpretation and judgemental biases in social phobia versus depression.

Science.gov (United States)

Voncken, M J; Bögels, S M; Peeters, F

2007-09-01

A body of studies shows that social phobia is characterized by content specific interpretation and judgmental biases. That is, they show bias in social situations but not in non-social situations. Comorbid depression, one of the major comorbid disorders in social phobia, might account for these biases in social phobia since depression also is characterized by cognitive distortions in social situations. This study hypothesized that, despite comorbid depression, patients with social phobia would suffer from contentspecific biases. Participants filled out the Interpretation and Judgmental Questionnaire (IJQ) to assess interpretation bias (using open-ended responses and forced-interpretations) and judgmental bias in social and non-social situations. Four groups participated: social phobic patients with high (N=38) and low (N=47) depressive symptoms, depressed patients (N=22) and normal controls (N=33). We found both social phobic groups to interpret social situations more negatively and judge social situations as more threatening than non-social situations relative to depressed patients and normal controls. As expected, depressive symptoms related to increased general interpretation and judgmental biases across social and non-social situations. In contrast to expectations, we did not find these patterns for the open-ended measure of interpretation bias. The content-specific biases for social situations distinguished social phobic patients from depressive patients. This speaks for the importance of establishing the primary diagnosis in patients with mixed depression and social anxiety complaints.

Common method biases in behavioral research: a critical review of the literature and recommended remedies.

Science.gov (United States)

Podsakoff, Philip M; MacKenzie, Scott B; Lee, Jeong-Yeon; Podsakoff, Nathan P

2003-10-01

Interest in the problem of method biases has a long history in the behavioral sciences. Despite this, a comprehensive summary of the potential sources of method biases and how to control for them does not exist. Therefore, the purpose of this article is to examine the extent to which method biases influence behavioral research results, identify potential sources of method biases, discuss the cognitive processes through which method biases influence responses to measures, evaluate the many different procedural and statistical techniques that can be used to control method biases, and provide recommendations for how to select appropriate procedural and statistical remedies for different types of research settings.

Are Teacher Course Evaluations Biased against Faculty That Teach Quantitative Methods Courses?

Science.gov (United States)

Royal, Kenneth D.; Stockdale, Myrah R.

2015-01-01

The present study investigated graduate students' responses to teacher/course evaluations (TCE) to determine if students' responses were inherently biased against faculty who teach quantitative methods courses. Item response theory (IRT) and Differential Item Functioning (DIF) techniques were utilized for data analysis. Results indicate students…

CPI Bias in Korea

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Chul Chung

2007-12-01

Full Text Available We estimate the CPI bias in Korea by employing the approach of Engel’s Law as suggested by Hamilton (2001. This paper is the first attempt to estimate the bias using Korean panel data, Korean Labor and Income Panel Study(KLIPS. Following Hamilton’s model with non­linear specification correction, our estimation result shows that the cumulative CPI bias over the sample period (2000-2005 was 0.7 percent annually. This CPI bias implies that about 21 percent of the inflation rate during the period can be attributed to the bias. In light of purchasing power parity, we provide an interpretation of the estimated bias.

An algorithm to assess methodological quality of nutrition and mortality cross-sectional surveys: development and application to surveys conducted in Darfur, Sudan

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Prudhon Claudine

2011-11-01

Full Text Available Abstract Background Nutrition and mortality surveys are the main tools whereby evidence on the health status of populations affected by disasters and armed conflict is quantified and monitored over time. Several reviews have consistently revealed a lack of rigor in many surveys. We describe an algorithm for analyzing nutritional and mortality survey reports to identify a comprehensive range of errors that may result in sampling, response, or measurement biases and score quality. We apply the algorithm to surveys conducted in Darfur, Sudan. Methods We developed an algorithm based on internationally agreed upon methods and best practices. Penalties are attributed for a list of errors, and an overall score is built from the summation of penalties accrued by the survey as a whole. To test the algorithm reproducibility, it was independently applied by three raters on 30 randomly selected survey reports. The algorithm was further applied to more than 100 surveys conducted in Darfur, Sudan. Results The Intra Class Correlation coefficient was 0.79 for mortality surveys and 0.78 for nutrition surveys. The overall median quality score and range of about 100 surveys conducted in Darfur were 0.60 (0.12-0.93 and 0.675 (0.23-0.86 for mortality and nutrition surveys, respectively. They varied between the organizations conducting the surveys, with no major trend over time. Conclusion Our study suggests that it is possible to systematically assess quality of surveys and reveals considerable problems with the quality of nutritional and particularly mortality surveys conducted in the Darfur crisis.

High bias gas flows increase lung injury in the ventilated preterm lamb.

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Katinka P Bach

Full Text Available BACKGROUND: Mechanical ventilation of preterm babies increases survival but can also cause ventilator-induced lung injury (VILI, leading to the development of bronchopulmonary dysplasia (BPD. It is not known whether shear stress injury from gases flowing into the preterm lung during ventilation contributes to VILI. METHODS: Preterm lambs of 131 days' gestation (term = 147 d were ventilated for 2 hours with a bias gas flow of 8 L/min (n = 13, 18 L/min (n = 12 or 28 L/min (n = 14. Physiological parameters were measured continuously and lung injury was assessed by measuring mRNA expression of early injury response genes and by histological analysis. Control lung tissue was collected from unventilated age-matched fetuses. Data were analysed by ANOVA with a Tukey post-hoc test when appropriate. RESULTS: High bias gas flows resulted in higher ventilator pressures, shorter inflation times and decreased ventilator efficiency. The rate of rise of inspiratory gas flow was greatest, and pulmonary mRNA levels of the injury markers, EGR1 and CTGF, were highest in lambs ventilated with bias gas flows of 18 L/min. High bias gas flows resulted in increased cellular proliferation and abnormal deposition of elastin, collagen and myofibroblasts in the lung. CONCLUSIONS: High ventilator bias gas flows resulted in increased lung injury, with up-regulation of acute early response genes and increased histological lung injury. Bias gas flows may, therefore, contribute to VILI and BPD.

Dropout Rates and Response Times of an Occupation Search Tree in a Web Survey

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Tijdens Kea

2014-03-01

Full Text Available Occupation is key in socioeconomic research. As in other survey modes, most web surveys use an open-ended question for occupation, though the absence of interviewers elicits unidentifiable or aggregated responses. Unlike other modes, web surveys can use a search tree with an occupation database. They are hardly ever used, but this may change due to technical advancements. This article evaluates a three-step search tree with 1,700 occupational titles, used in the 2010 multilingual WageIndicator web survey for UK, Belgium and Netherlands (22,990 observations. Dropout rates are high; in Step 1 due to unemployed respondents judging the question not to be adequate, and in Step 3 due to search tree item length. Median response times are substantial due to search tree item length, dropout in the next step and invalid occupations ticked. Overall the validity of the occupation data is rather good, 1.7-7.5% of the respondents completing the search tree have ticked an invalid occupation.

Profiling the mobile-only population in Australia: insights from the Australian National Health Survey.

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Baffour, Bernard; Haynes, Michele; Dinsdale, Shane; Western, Mark; Pennay, Darren

2016-10-01

The Australian population that relies on mobile phones exclusively has increased from 5% in 2005 to 29% in 2014. Failing to include this mobile-only population leads to a potential bias in estimates from landline-based telephone surveys. This paper considers the impacts on selected health prevalence estimates with and without the mobile-only population. Using data from the Australian Health Survey - which, for the first time, included a question on telephone status - we examined demographic, geographic and health differences between the landline-accessible and mobile-only population. These groups were also compared to the full population, controlling for the sampling design and differential non-response patterns in the observed sample through weighting and benchmarking. The landline-accessible population differs from the mobile-only population for selected health measures resulting in biased prevalence estimates for smoking, alcohol risk and private health insurance coverage in the full population. The differences remain even after adjusting for age and gender. Using landline telephones only for conducting population health surveys will have an impact on prevalence rate estimates of health risk factors due to the differing profiles of the mobile-only population from the landline-accessible population. © 2016 Public Health Association of Australia.

Effects of the leakage magnetic field from an analog meter on the response of scintillation survey meters

International Nuclear Information System (INIS)

Abe, Toshiaki; Yamamoto, Hisao; Norimura, Toshiyuki; Katase, Akira

2003-01-01

Effects of the weak leakage magnetic field are studied on the response of two kinds of scintillation survey meters: an ordinary type for γ-rays and that optimized for the detection of low-energy photons from 125 I. In the presence of the magnetic field, the response of the optimized survey meter decreases to the photons from 125 I, and increases considerably to the background radiations. On the other hand, the response of the ordinary survey meter decreases slightly to both the γ-rays from 131 I and the background radiations. From analysis of the pulse-height spectra for the radiations, such variations of the response are ascribed to the reduction of the amplification factor of photomultiplier tubes by the magnetic field. (author)

Nonresponse Error in Mail Surveys: Top Ten Problems

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Jeanette M. Daly

2011-01-01

Full Text Available Conducting mail surveys can result in nonresponse error, which occurs when the potential participant is unwilling to participate or impossible to contact. Nonresponse can result in a reduction in precision of the study and may bias results. The purpose of this paper is to describe and make readers aware of a top ten list of mailed survey problems affecting the response rate encountered over time with different research projects, while utilizing the Dillman Total Design Method. Ten nonresponse error problems were identified, such as inserter machine gets sequence out of order, capitalization in databases, and mailing discarded by postal service. These ten mishaps can potentiate nonresponse errors, but there are ways to minimize their frequency. Suggestions offered stem from our own experiences during research projects. Our goal is to increase researchers' knowledge of nonresponse error problems and to offer solutions which can decrease nonresponse error in future projects.

Consumer attitudes on cough and cold: US (ACHOO) survey results.

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Blaiss, M S; Dicpinigaitis, P V; Eccles, R; Wingertzahn, M A

2015-08-01

The Attitudes of Consumers Toward Health, Cough, and Cold (ACHOO) survey was developed to better inform health care providers on the natural history and impact of common cold and cough, and related consumer experience and behaviors. Randomly selected US Internet/mobile device users were invited to participate in an online survey (N = 3333) in October 2012. Response quotas modeled upon 2010 US Census data ensured a demographically representative sample. To reduce potential bias from the quota design, 75% of the completed surveys were randomly selected as the primary analysis pool. Survey questions assessed participant demographics, frequency and duration of cough/cold symptoms, impact of symptoms on daily life, treatment preferences, and knowledge about cough/cold pathophysiology. In the past year, 84.6% of respondents had experienced at least one cold. Colds typically started with sore/scratchy throat (39.2%), nasal congestion (9.8%), and runny nose (9.3%) and lasted 3-7 days. Cough, the most common cold symptom (73.1%), had a delayed onset (typically 1-5 days after cold onset) and a long duration (>6 days in 35.2%). Nasal congestion and cough were the most bothersome symptoms. Many respondents waited until symptoms were 'bad enough' (42.6%) or multiple symptoms were present (20.2%) before using nonprescription medications. Drivers of choice included effectiveness in relieving symptoms, safety, and past experience. Respondents rarely consulted clinicians regarding treatment, and more than three-quarters had never received instructions from a clinician on how to choose a nonprescription cough/cold medication. Misperceptions regarding etiology and treatment of the common cold were prevalent. The main limitation is potential recall bias, since respondents had to recall cough/cold episodes over the prior year. The ACHOO survey confirms that cold is a common, bothersome experience and that there are gaps in consumers' knowledge of pathophysiology and appropriate

THE NONLINEAR BIASING OF THE zCOSMOS GALAXIES UP TO z ∼ 1 FROM THE 10k SAMPLE

International Nuclear Information System (INIS)

Kovac, K.; Porciani, C.; Lilly, S. J.; Oesch, P.; Peng, Y.; Carollo, C. M.; Marinoni, C.; Guzzo, L.; Iovino, A.; Cucciati, O.; Kneib, J.-P.; Le Fevre, O.; Zamorani, G.; Bolzonella, M.; Zucca, E.; Bardelli, S.; Meneux, B.; Contini, T.; Mainieri, V.; Renzini, A.

2011-01-01

We use the zCOSMOS galaxy overdensity field to study the biasing of galaxies in the COSMOS field. By comparing the probability distribution function of the galaxy density contrast δ g to the lognormal approximation of the mass density contrast δ, we obtain the mean biasing function b(δ, z, R) between the galaxy and matter overdensity fields and its second moments b-hat and b-tilde. Over the redshift interval 0.4 g |δ) = b(δ, z, R)δ is of a characteristic shape, requiring nonlinear biasing in the most overdense and underdense regions. Taking into account the uncertainties due to cosmic variance, we do not detect any significant evolution in the (δ g |δ) function, but we do detect a significant redshift evolution in the linear biasing parameter b-hat from 1.23 ± 0.11 at z ∼ 0.55 to 1.62 ± 0.14 at z ∼ 0.75, for a luminosity-complete sample of M B -1 Mpc, but increases systematically with luminosity (at 2σ-3σ significance between the M B B B 12 M sun with a small dependence on the adopted bias-mass relation. Our detailed error analysis and comparison with previous studies lead us to conclude that cosmic variance is the main contributor to the differences in the linear bias measured from different surveys. While our results support the general picture of biased galaxy formation up to z ∼ 1, the fine-tuning of the galaxy formation models is still limited by the restrictions of the current spectroscopic surveys at these redshifts.

Student Evaluation of Teaching: An Investigation of Nonresponse Bias in an Online Context

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Reisenwitz, Timothy H.

2016-01-01

The online administration of student evaluations has its shortcomings, including low participation, or low response rates, and bias. This study examines nonresponse bias in online student evaluations of instruction, that is, the differences between those students who complete online evaluations and those who decide not to complete them. It builds…

A selective emotional decision-making bias elicited by facial expressions.

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Nicholas Furl

Full Text Available Emotional and social information can sway otherwise rational decisions. For example, when participants decide between two faces that are probabilistically rewarded, they make biased choices that favor smiling relative to angry faces. This bias may arise because facial expressions evoke positive and negative emotional responses, which in turn may motivate social approach and avoidance. We tested a wide range of pictures that evoke emotions or convey social information, including animals, words, foods, a variety of scenes, and faces differing in trustworthiness or attractiveness, but we found only facial expressions biased decisions. Our results extend brain imaging and pharmacological findings, which suggest that a brain mechanism supporting social interaction may be involved. Facial expressions appear to exert special influence over this social interaction mechanism, one capable of biasing otherwise rational choices. These results illustrate that only specific types of emotional experiences can best sway our choices.

A Selective Emotional Decision-Making Bias Elicited by Facial Expressions

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Furl, Nicholas; Gallagher, Shannon; Averbeck, Bruno B.

2012-01-01

Emotional and social information can sway otherwise rational decisions. For example, when participants decide between two faces that are probabilistically rewarded, they make biased choices that favor smiling relative to angry faces. This bias may arise because facial expressions evoke positive and negative emotional responses, which in turn may motivate social approach and avoidance. We tested a wide range of pictures that evoke emotions or convey social information, including animals, words, foods, a variety of scenes, and faces differing in trustworthiness or attractiveness, but we found only facial expressions biased decisions. Our results extend brain imaging and pharmacological findings, which suggest that a brain mechanism supporting social interaction may be involved. Facial expressions appear to exert special influence over this social interaction mechanism, one capable of biasing otherwise rational choices. These results illustrate that only specific types of emotional experiences can best sway our choices. PMID:22438936

A selective emotional decision-making bias elicited by facial expressions.

Science.gov (United States)

Furl, Nicholas; Gallagher, Shannon; Averbeck, Bruno B

2012-01-01

Emotional and social information can sway otherwise rational decisions. For example, when participants decide between two faces that are probabilistically rewarded, they make biased choices that favor smiling relative to angry faces. This bias may arise because facial expressions evoke positive and negative emotional responses, which in turn may motivate social approach and avoidance. We tested a wide range of pictures that evoke emotions or convey social information, including animals, words, foods, a variety of scenes, and faces differing in trustworthiness or attractiveness, but we found only facial expressions biased decisions. Our results extend brain imaging and pharmacological findings, which suggest that a brain mechanism supporting social interaction may be involved. Facial expressions appear to exert special influence over this social interaction mechanism, one capable of biasing otherwise rational choices. These results illustrate that only specific types of emotional experiences can best sway our choices.

Pairing call-response surveys and distance sampling for a mammalian carnivore

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Hansen, Sara J. K.; Frair, Jacqueline L.; Underwood, Harold B.; Gibbs, James P.

2015-01-01

Density estimates accounting for differential animal detectability are difficult to acquire for wide-ranging and elusive species such as mammalian carnivores. Pairing distance sampling with call-response surveys may provide an efficient means of tracking changes in populations of coyotes (Canis latrans), a species of particular interest in the eastern United States. Blind field trials in rural New York State indicated 119-m linear error for triangulated coyote calls, and a 1.8-km distance threshold for call detectability, which was sufficient to estimate a detection function with precision using distance sampling. We conducted statewide road-based surveys with sampling locations spaced ≥6 km apart from June to August 2010. Each detected call (be it a single or group) counted as a single object, representing 1 territorial pair, because of uncertainty in the number of vocalizing animals. From 524 survey points and 75 detections, we estimated the probability of detecting a calling coyote to be 0.17 ± 0.02 SE, yielding a detection-corrected index of 0.75 pairs/10 km2 (95% CI: 0.52–1.1, 18.5% CV) for a minimum of 8,133 pairs across rural New York State. Importantly, we consider this an index rather than true estimate of abundance given the unknown probability of coyote availability for detection during our surveys. Even so, pairing distance sampling with call-response surveys provided a novel, efficient, and noninvasive means of monitoring populations of wide-ranging and elusive, albeit reliably vocal, mammalian carnivores. Our approach offers an effective new means of tracking species like coyotes, one that is readily extendable to other species and geographic extents, provided key assumptions of distance sampling are met.

SAGES climate survey: results and strategic planning for our future.

Science.gov (United States)

Telem, Dana A; Qureshi, Alia; Edwards, Michael; Jones, Daniel B

2018-03-30

While SAGES prides itself on diversity and inclusivity, we also recognize that as an organization we are not impervious to blind spots impacting equity within the membership. To address this, the We R Sages task force was formed to identify the barriers and facilitators to creating a diverse organization and develop a strategic plan for the implementation of programing and opportunities that promote diversity and inclusivity within our membership. As the first step in the process, a survey was administered to gauge the current organizational climate. In September of 2017, a validated climate survey was administered to 704 SAGES committee members via SurveyMonkey®. Climate was assessed on: overall SAGES experience, consideration of leaving the organization, mentorship within the organization, resources and opportunities within the organization, and attitudes and experiences within the organization. Additional free text responses were encouraged to generate qualitative themes. The survey response rate was 52.1% (n = 367). Respondent self-identified demographics were: male (73%), white (63%), heterosexual (95.5%), and non-disabled (98%). Average overall satisfaction was 8.1/10. 12.5% of respondents had considered leaving the organization and 74.4% had not identified a formal mentor within the organization. Average agreement with equitable distribution of resources and opportunities was 5.8/10. 93.6% of respondents had not experienced bias within the organization. Overall SAGES has a very positive climate; however, several key issues were identified from the quantitative survey as well as the free text responses. Strategic planning to address issues of membership recruitment, committee engagement, advancement transparency, diversity awareness, leadership development, and formal mentorship are being implemented.

Approximate Bias Correction in Econometrics

OpenAIRE

James G. MacKinnon; Anthony A. Smith Jr.

1995-01-01

This paper discusses ways to reduce the bias of consistent estimators that are biased in finite samples. It is necessary that the bias function, which relates parameter values to bias, should be estimable by computer simulation or by some other method. If so, bias can be reduced or, in some cases that may not be unrealistic, even eliminated. In general, several evaluations of the bias function will be required to do this. Unfortunately, reducing bias may increase the variance, or even the mea...

Detecting rater bias using a person-fit statistic: a Monte Carlo simulation study.

Science.gov (United States)

Aubin, André-Sébastien; St-Onge, Christina; Renaud, Jean-Sébastien

2018-04-01

With the Standards voicing concern for the appropriateness of response processes, we need to explore strategies that would allow us to identify inappropriate rater response processes. Although certain statistics can be used to help detect rater bias, their use is complicated by either a lack of data about their actual power to detect rater bias or the difficulty related to their application in the context of health professions education. This exploratory study aimed to establish the worthiness of pursuing the use of l z to detect rater bias. We conducted a Monte Carlo simulation study to investigate the power of a specific detection statistic, that is: the standardized likelihood l z person-fit statistics (PFS). Our primary outcome was the detection rate of biased raters, namely: raters whom we manipulated into being either stringent (giving lower scores) or lenient (giving higher scores), using the l z statistic while controlling for the number of biased raters in a sample (6 levels) and the rate of bias per rater (6 levels). Overall, stringent raters (M = 0.84, SD = 0.23) were easier to detect than lenient raters (M = 0.31, SD = 0.28). More biased raters were easier to detect then less biased raters (60% bias: 62, SD = 0.37; 10% bias: 43, SD = 0.36). The PFS l z seems to offer an interesting potential to identify biased raters. We observed detection rates as high as 90% for stringent raters, for whom we manipulated more than half their checklist. Although we observed very interesting results, we cannot generalize these results to the use of PFS with estimated item/station parameters or real data. Such studies should be conducted to assess the feasibility of using PFS to identify rater bias.

Comparing Two Inferential Approaches to Handling Measurement Error in Mixed-Mode Surveys

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Buelens Bart

2017-06-01

Full Text Available Nowadays sample survey data collection strategies combine web, telephone, face-to-face, or other modes of interviewing in a sequential fashion. Measurement bias of survey estimates of means and totals are composed of different mode-dependent measurement errors as each data collection mode has its own associated measurement error. This article contains an appraisal of two recently proposed methods of inference in this setting. The first is a calibration adjustment to the survey weights so as to balance the survey response to a prespecified distribution of the respondents over the modes. The second is a prediction method that seeks to correct measurements towards a benchmark mode. The two methods are motivated differently but at the same time coincide in some circumstances and agree in terms of required assumptions. The methods are applied to the Labour Force Survey in the Netherlands and are found to provide almost identical estimates of the number of unemployed. Each method has its own specific merits. Both can be applied easily in practice as they do not require additional data collection beyond the regular sequential mixed-mode survey, an attractive element for national statistical institutes and other survey organisations.

Survey Satisficing Inflates Stereotypical Responses in Online Experiment: The Case of Immigration Study

Science.gov (United States)

Miura, Asako; Kobayashi, Tetsuro

2016-01-01

Though survey satisficing, grudging cognitive efforts required to provide optimal answers in the survey response process, poses a serious threat to the validity of online experiments, a detailed explanation of the mechanism has yet to be established. Focusing on attitudes toward immigrants, we examined the mechanism by which survey satisficing distorts treatment effect estimates in online experiments. We hypothesized that satisficers would display more stereotypical responses than non-satisficers would when presented with stereotype-disconfirming information about an immigrant. Results of two experiments largely supported our hypotheses. Satisficers, whom we identified through an instructional manipulation check (IMC), processed information about immigrants' personality traits congruently with the stereotype activated by information provided about nationality. The significantly shorter vignette reading time of satisficers corroborates their time-efficient impression formation based on stereotyping. However, the shallow information processing of satisficers can be rectified by alerting them to their inattentiveness through use of a repeated IMC. PMID:27803680

Beliefs Alter Holistic Face Processing…If Response Bias is not Taken into Account

Science.gov (United States)

Richler, Jennifer J.; Cheung, Olivia S.; Gauthier, Isabel

2012-01-01

The composite paradigm is widely used to quantify holistic processing (HP) of faces, but there is debate regarding the appropriate design (partial vs. complete) and measures in this task. Here, we argue that some operational definitions of HP are problematic because they are sensitive to top-down influences, even though the underlying concept is assumed to be cognitively impenetrable. In Experiment 1, we told one group of participants that the target face half would remain the same on 75% of trials, and another group that it would change on 75% of trials. The true proportion of same/different trials was 50% - groups only differed in their beliefs about the target halves. In Experiment 2, we manipulated the actual proportion of same/different trials in the experiment (75% of trials were same for one group, 75% of trials were different for another group), but did not give explicit instructions about proportions. In both experiments these manipulations influenced response biases that altered partial design measures of HP while the complete design measure was unaffected. We argue that the partial design should be abandoned because it has poor construct validity. PMID:22101018

Does courtesy bias affect how clients report on objective and subjective measures of family planning service quality? A comparison between facility- and home-based interviews.

Science.gov (United States)

Hameed, Waqas; Ishaque, Muhammad; Gul, Xaher; Siddiqui, Junaid-Ur-Rehman; Hussain, Sharmeen; Hussain, Wajahat; Ahmed, Aftab; Balal, Asma

2017-01-01

Despite a general understanding that exit interviews being conducted at service providers' facilities may influence clients' responses favorably to health professionals, there is very little evidence available that demonstrates the extent to which this problem exists. This study aimed at assessing and comparing clients' perceptions of the quality of family planning services and their satisfaction levels between facility- and home-based interviews. A cross-sectional survey was conducted among clients receiving family planning services across three service delivery channels - nongovernmental organization (NGO) clinics, social franchise (SF) centers, and outreach camps. The survey took place from December 2015 to January 2016 in 70 districts across all four provinces of Pakistan. A total of 2,807 clients were interviewed, of whom 1,404 clients were interviewed at health facilities after receiving services and 1,403 were interviewed at their homes within 3 days of method uptake. Overall, we found no significant differences between the characteristics of study participants interviewed at health facilities or at home. The findings suggested that experiences reported in exit surveys at facilities were strongly biased positively. This was true for both experiential (service quality) and perception-based (satisfaction) questions in the context of SF centers, while at NGO clinics the interview location only affected clients' responses regarding service quality. However, in outreach settings, clients are more likely to share bad experiences in exit interviews than in home-based interviews on objectively asked questions (service quality). Our study indicates signs of courtesy bias and possibly the Hawthorne effect in exit interviews. Program implementers could opt for home-based interviews for women receiving services at NGO clinics or SF center, whereas exit interviews could be used in outreach settings.

Cyber and bias-based harassment: associations with academic, substance use, and mental health problems.

Science.gov (United States)

Sinclair, Katerina O; Bauman, Sheri; Poteat, V Paul; Koenig, Brian; Russell, Stephen T

2012-05-01

To examine how two forms of interstudent harassment, cyber and bias-based harassment, are associated with academic, substance use, and mental health problems. We used a population-based survey of 17,366 middle and high school students that assessed harassment due to race/ethnicity or sexual orientation, and harassment through the Internet or text messaging along with other forms of interstudent harassment. Odds ratios indicated that students experiencing both cyber and bias-based harassment were at the greatest risk for adjustment problems across all indicators, with suicidal ideation and attempts having the largest risk differences. Assessments of adolescent health and adjustment should include questions regarding both cyber and bias-based harassment. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

A scanning tunneling microscope break junction method with continuous bias modulation.

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Beall, Edward; Yin, Xing; Waldeck, David H; Wierzbinski, Emil

2015-09-28

Single molecule conductance measurements on 1,8-octanedithiol were performed using the scanning tunneling microscope break junction method with an externally controlled modulation of the bias voltage. Application of an AC voltage is shown to improve the signal to noise ratio of low current (low conductance) measurements as compared to the DC bias method. The experimental results show that the current response of the molecule(s) trapped in the junction and the solvent media to the bias modulation can be qualitatively different. A model RC circuit which accommodates both the molecule and the solvent is proposed to analyze the data and extract a conductance for the molecule.

Survey of basic medical researchers on the awareness of animal experimental designs and reporting standards in China.

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Bin Ma

Full Text Available To investigate the awareness and use of the Systematic Review Center for Laboratory Animal Experimentation's (SYRCLE risk-of-bias tool, the Animal Research: Reporting of In Vivo Experiments (ARRIVE reporting guidelines, and Gold Standard Publication Checklist (GSPC in China in basic medical researchers of animal experimental studies.A national questionnaire-based survey targeting basic medical researchers was carried in China to investigate the basic information and awareness of SYRCLE's risk of bias tool, ARRIVE guidelines, GSPC, and animal experimental bias risk control factors. The EpiData3.1 software was used for data entry, and Microsoft Excel 2013 was used for statistical analysis in this study. The number of cases (n and percentage (% of classified information were statistically described, and the comparison between groups (i.e., current students vs. research staff was performed using chi-square test.A total of 298 questionnaires were distributed, and 272 responses were received, which included 266 valid questionnaires (from 118 current students and 148 research staff. Among the 266 survey participants, only 15.8% was aware of the SYRCLE's risk of bias tool, with significant difference between the two groups (P = 0.003, and the awareness rates of ARRIVE guidelines and GSPC were only 9.4% and 9.0%, respectively; 58.6% survey participants believed that the reports of animal experimental studies in Chinese literature were inadequate, with significant difference between the two groups (P = 0.004. In addition, only approximately 1/3 of the survey participants had read systematic reviews and meta-analysis reports of animal experimental studies; only 16/266 (6.0% had carried out/participated in and 11/266 (4.1% had published systematic reviews/meta-analysis of animal experimental studies.The awareness and use rates of SYRCLE's risk-of-bias tool, the ARRIVE guidelines, and the GSPC were low among Chinese basic medical researchers. Therefore

Is in-group bias culture-dependent? A meta-analysis across 18 societies.

Science.gov (United States)

Fischer, Ronald; Derham, Crysta

2016-01-01