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Test-retest reliability is often estimated using naturally occurring data from test repeaters. In settings such as admissions testing, test takers choose if and when to retake an assessment. This self-selection can bias estimates of test-retest reliability because individuals who choose to retest are typically unrepresentative of the broader testing population and because differences among test takers in learning or practice effects may increase with time between test administrations. We develop a set of methods for estimating test-retest reliability from observational data that can mitigate these sources of bias, which include sample weighting, polynomial regression, and Bayesian model averaging. We demonstrate the value of using these methods for reducing bias and improving precision of estimated reliability using empirical and simulated data, both of which are based on more than 40,000 repeaters of a high-stakes English language proficiency test. Finally, these methods generalize to settings in which only a single, error-prone measurement is taken repeatedly over time and where self-selection and/or changes to the underlying construct may be at play. [ABSTRACT FROM AUTHOR]

Natural resources such as soil and water are essential to agriculture, especially in arid and semi-arid rain-fed areas, yet the impacts of managing these crucial natural resources on farm technical efficiency are little known. Using data from 400 households with 1031 plots, we examined the impacts of soil and water conservation measures (SWCMs) on the technical efficiency of farmers in the semi-arid Bundelkhand (central India). We estimated stochastic production frontiers, considering potential self-selection bias stemming from both observable and unobservable factors in the adoption of SWCMs at the farm level. The farm technical efficiency for adopters of SWCMs ranged from 0.68 to 0.72, and that for non-adopters ranged from 0.52 to 0.65, depending on how biases were controlled for. As the average efficiency is consistently higher for adopter farmers than the control group, promoting SWCMs could help to increase input use efficiency, especially in resource-deprived rain-fed systems in the semi-arid tropics. [ABSTRACT FROM AUTHOR]

Background Empirical evaluation of inverse probability weighting (IPW) for self-selection bias correction is inaccessible without the full source population. We aimed to: (i) investigate how self-selection biases frequency and association measures and (ii) assess self-selection bias correction using IPW in a cohort with register linkage. Methods The source population included 17 936 individuals invited to the Copenhagen Aging and Midlife Biobank during 2009–11 (ages 49–63 years). Participants counted 7185 (40.1%). Register data were obtained for every invited person from 7 years before invitation to the end of 2020. The association between education and mortality was estimated using Cox regression models among participants, IPW participants and the source population. Results Participants had higher socioeconomic position and fewer hospital contacts before baseline than the source population. Frequency measures of participants approached those of the source population after IPW. Compared with primary/lower secondary education, upper secondary, short tertiary, bachelor and master/doctoral were associated with reduced risk of death among participants (adjusted hazard ratio [95% CI]: 0.60 [0.46; 0.77], 0.68 [0.42; 1.11], 0.37 [0.25; 0.54], 0.28 [0.18; 0.46], respectively). IPW changed the estimates marginally (0.59 [0.45; 0.77], 0.57 [0.34; 0.93], 0.34 [0.23; 0.50], 0.24 [0.15; 0.39]) but not only towards those of the source population (0.57 [0.51; 0.64], 0.43 [0.32; 0.60], 0.38 [0.32; 0.47], 0.22 [0.16; 0.29]). Conclusions Frequency measures of study participants may not reflect the source population in the presence of self-selection, but the impact on association measures can be limited. IPW may be useful for (self-)selection bias correction, but the returned results can still reflect residual or other biases and random errors. [ABSTRACT FROM AUTHOR]

This article aims to compare the pattern of responses obtained by a web-based and a paper-based survey used to investigate the transit safety of travellers in railway stations in Sweden. This aim is achieved by evaluating whether the response and the completion rates change as the surveys progress, assessing the effect of the survey mode on respondents' answers (after controlling for the surveys' internal consistency and differences in the samples), and the potential impact of the order of alternatives in multiple-choice questions on the responses. To carry out the study, a sample of 500 responses was taken from each population and later compared using a series of statistical tests. Findings indicate that despite the surveys' high internal consistency, the prevalence of victimisation, fear of crime, and precautions detected in the web survey was higher than those found in the paper survey. The web survey shows a major drop just after the initial questions, while the paper survey shows a more stable pattern of responses, but was also affected by a single compulsory question that pushed the completion rate down. Finally, the order of alternatives in multiple-choice questions (fixed or random) did not affect the answers given by the respondents, providing a solid base for safety interventions in transit environments, regardless of survey mode. The article concludes by making suggestions for both research and practice. [ABSTRACT FROM AUTHOR]

The dissemination of conservation agriculture (CA) technologies has become the objective of a growing number of projects aimed at reducing food insecurity in vulnerable areas of the world. While many studies have found that CA increases farm productivity, little is known about the components of the productivity gains related to CA adoption. CA is a knowledge‐intensive technology, and it is expected to affect both technical efficiency (TE) and input productivity positively. Using cross‐sectional farm‐level data of 220 maize farmers in Bangladesh, we measure the impact of CA on farmers' TE. We first apply propensity score matching (PSM) to create comparable counterfactual groups of CA and non‐CA farmers. Then, we use a stochastic frontier with correction for self‐selection bias to analyse TE. Finally, we fit a stochastic meta‐frontier (SMF) model to the data and use it to compare TE across the two farmer groups. The analysis showed that CA farmers exhibit greater TE levels than non‐CA farmers. This can be attributed to enhancements in farm management, leading to 8% and 9% increases in their productivity and TE, respectively. Thus, there is a case for policymakers to strengthen programs delivering CA technologies that improve food security in Bangladesh. [ABSTRACT FROM AUTHOR]

Declining survey response rates have increased the costs of travel survey recruitment. Recruiting respondents based on their expressed willingness to participate in future surveys, obtained from a preceding survey, is a potential solution but may exacerbate sample biases. In this study, we analyze the self-selection biases of survey respondents recruited from the 2017 U.S. National Household Travel Survey (NHTS), who had agreed to be contacted again for follow-up surveys. We apply a probit with sample selection (PSS) model to analyze (1) respondents' willingness to participate in a follow-up survey (the selection model) and (2) their actual response behavior once contacted (the outcome model). Results verify the existence of self-selection biases, which are related to survey burden, sociodemographic characteristics, travel behavior, and item non-response to sensitive variables. We find that age, homeownership, and medical conditions have opposing effects on respondents' willingness to participate and their actual survey participation. The PSS model is then validated using a hold-out sample and applied to the NHTS samples from various geographic regions to predict follow-up survey participation. Effect size indicators for differences between predicted and actual (population) distributions of select sociodemographic and travel-related variables suggest that the resulting samples may be most biased along age and education dimensions. Further, we summarized six model performance measures based on the PSS model structure. Overall, this study provides insight into self-selection biases in respondents recruited from preceding travel surveys. Model results can help researchers better understand and address such biases, while the nuanced application of various model measures lays a foundation for appropriate comparison across sample selection models. [ABSTRACT FROM AUTHOR]

Camping is a recreational activity that links people with their physical surroundings and the environment. Hence, efforts in promoting camping activities may help promote sustainable and accessible recreation and tourism. This research focuses on preferences and barriers for camping in Israel as perceived by frequent, occasional, and noncampers. The findings of an online study with 665 respondents show that focusing only on current campers may create self-selection bias and overlook the barriers that prevent people from camping. While noncampers shared some barriers with campers, they also experienced more barriers regarding information gaps (location of campsites) and camping equipment. All participants had a similar preference for solitude and lack of crowding. These findings create a dilemma for camping managers and marketing campaigns: to reduce the barriers that prevent low frequency campers and noncampers from camping or to keep the situation as is and minimize overcrowding in campsites. [ABSTRACT FROM AUTHOR]

We examine a potential self‐selection bias in different samples of experimental subjects depending on the payment scheme offered in the recruiting process. We ran four field experiments in which undergraduate students in a microeconomics course were invited to voluntarily set their own goal for the final exam. They were informed that they would be given a monetary reward (else nothing) if their actual grade were higher than or equal to their goal. Rewards were an increasing (quadratic) function of the goal. We aimed at studying whether subjects' willingness to participate in the experiment depends on their expected performance under different advertised reward criteria, like a rank‐order tournament and piece‐rate pay. Given that judgments about future performance are closely tied to previous performance, the midterm exam scores from the current academic course are compared between participants and nonparticipants in order to analyze sample‐sorting effects. We find that when a rank‐order tournament is offered alone or in combination with another reward mechanism, high‐performing students are more likely than low‐performing ones to participate in the experiment. [ABSTRACT FROM AUTHOR]

Copyright of Contaduría y Administración is the property of Facultad de Contaduria y Administracion-Universidad Nacional Autonoma de Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

While most previous studies in the Western context have found a positive correlation between volunteering and health, this positive relation is not conclusive since the self-selection bias inherent in this question has not been addressed well. Meanwhile, this relation has been rarely explored in non-Western countries, especially mainland China, where institutionalized volunteer practices are more emergent. Using a nationally representative sample (N = 4967) from the 2013 Survey on Philanthropic Behaviors of Urban Citizens in China, this study followed the counterfactual framework under quasi-experimental design and adopted two treatment effects models - propensity score matching and nearest neighbor matching - to detect the net effect of volunteering on individuals' self-rated health. Analyses from both matching models consistently indicate that after conditioning on the covariates, volunteers on average, have a higher self-rated health score than non-volunteers. The results also provide evidence of upward bias about the positive effect of volunteering on health in models that use standard multiple regression approach. In sum, the findings demonstrate that volunteering is a real benefit for health, but the positive effect is likely to be overestimated when self-selection bias is not accounted for. Finally, this study presents new evidence that the positive effect of volunteering is consistent across national boundaries to the Chinese context. [ABSTRACT FROM AUTHOR]

Beef quality assurance initiatives have been developed to assure consumers of the quality and safety of supplied beef, as well as the environmental‐orientation of farm production practices. However, the potential economic benefits of quality schemes to European beef cattle farmers have been overlooked. This paper uses farm‐level data to identify the drivers of Irish farmers' participation in Bord Bia's Beef and Lamb Quality Assurance Scheme (BLQAS) in 2012, and assesses the impact of participation on farm gross margins. After controlling for potential self‐selection bias, we cannot find reliable evidence that the gross margins of participants in beef quality assurance schemes have been affected by their decision to participate. Consequently, lack of financial incentives can be a barrier to farmer participation in beef quality assurance schemes [EconLit citations: L25, M21, Q12]. [ABSTRACT FROM AUTHOR]

Many researchers have identified the issue of self-selection bias hindering the ability to detect nutrient effects in healthy populations. However, it appears that no effort has been made to mitigate this potential design flaw. By recruiting individuals on the basis of pre-trial dietary intake, the Memory and Attention Supplementation Trial aimed to capture a cohort of participants with a wide variety of dietary intake, thus increasing the likelihood of a diverse range of nutrient status. This perspective specifically examines the profile of these trial volunteers and in doing so, we present the first empirical evidence of self-selection bias when recruiting healthy volunteers for a randomized controlled trial of a nutrient-based supplement. These findings support the anecdotal proposal that traditional recruitment methods inherently attract trial volunteers who are vastly unrepresentative of the population and threatens the generalizability of this field of research. Alternative approaches to recruitment, including a-priori screening for baseline diet quality and nutrient status, are discussed as essential design recommendations to ensure accurate interpretation of nutrient effects within the context of baseline participant characteristics.

Background: Participation bias in exercise studies is poorly understood among older adults. This study was aimed at looking into whether older persons who volunteer to participate in an exercise study differ from nonvolunteers. Methods: A self-reported questionnaire on physical activity and general health was mailed out to 1000 persons, aged 60 or over, who were covered by the medical insurance of the French National Education System. Among them, 535 answered it and sent it back. Two hundred and thirty-three persons (age 69.7 ±7.6, 65.7% women) said they would volunteer to participate in an exercise study and 270 (age 71.7 ±8.8, 62.2% women) did not. Results: Volunteers were younger and more educated than nonvolunteers, but they did not differ in sex. They had less physical function decline and higher volumes of physical activity than nonvolunteers. Compared with volunteers, nonvolunteers had a worse self-reported health and suffered more frequently from chronic pain. Multiple logistic regressions showed that good self-reported health, absence of chronic pain, and lower levels of physical function decline were associated with volunteering to participate in an exercise study. Conclusions: Volunteers were fitter and healthier than nonvolunteers. Therefore, caution must be taken when generalizing the results of exercise intervention studies. [ABSTRACT FROM AUTHOR]

Previous research suggests that participation in victim–offender mediation (VOM) can lower the risk of reoffending. However, no randomized controlled trials have been done to examine this effect of VOM. Given that participation in VOM is voluntary, previous studies likely suffer from self-selection bias. To address this bias, we compared reoffending rates of three different offender groups: offenders who participated in VOM; offenders who were willing to participate, but whose counterpart declined VOM; and offenders unwilling to participate (total N = 1,275). Results replicated that participation in VOM predicts lower reoffending rates and suggested that this effect is not solely due to a self-selection bias. Suggestions are made for future research to examine why VOM causes lower reoffending rates. [ABSTRACT FROM AUTHOR]

Copyright of Japanese Sociological Review / Shakaigaku Hyoron is the property of Japan Sociological Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

User-generated hotel ratings have been found to be an important element in customers' decision making. Nevertheless, most hotel ratings online show average ratings that are extremely positive. Thus, the question is raised of whether online ratings reflect objective evaluation of the reviewers. This study examines the distribution of online ratings and compares it the distribution of offline ratings. Online hotel score ratings reported on Booking.com were extracted and compared with offline rating scores from a field survey. Online and offline hotel ratings of eight hotels located in Seoul were collected. The ratings were compared using Welch's t-test. Overall, both online and offline ratings for all eight hotels show generally positive distribution curves. The distribution curves exhibit shapes analogous to those considered to contain self-selection bias. The randomized offline ratings did not produce more moderate ratings as predicted. Thus, no indication of non-response bias was found. Practically, this study supports the notion that hotels listed on online travel agencies such as Booking.com may already have passed certain quality criteria, thereby providing competitive marketplaces for customers searching for hotels online. [ABSTRACT FROM AUTHOR]

Summary: The general health check is one of the most common preventive healthcare measures in many countries. In this study, we propose an empirical approach which jointly models the decision to obtain a general health check and healthcare utilization, tackling the self‐selection problem by using eligibility to obtain a health check for free as an instrumental variable. Eligibility has some exogenous variations by design and this helps us to partial out the effect of general health checks from self‐selection biases. We apply the model to a large 12‐year panel data set provided by the Korean National Health Insurance Service. We find that participation in the general health check increases healthcare utilization and ignored self‐selection generates substantial upward bias in the estimates. We also find that the health check effect shows noteworthy heterogeneity across gender and income groups. Before health checks, healthcare utilization of males and people in low income groups is lower than those of females and people in high income groups respectively. However, these become comparable across different groups after health checks. This finding implies that general health checks can be an effective vehicle for health equity. [ABSTRACT FROM AUTHOR]

How does e-shopping impact household travel? To answer this question, which is particularly relevant for policymakers concerned with congestion, air pollution, and greenhouse gas emissions from transportation, we analyzed data from the 2017 National Household Travel Survey using propensity score matching. This allowed us to tackle the bias from households self-selecting into various levels of e-shopping and gain causal inference. Unlike other related papers in the literature, our unit of analysis is a household because travel and shopping decisions within a household are interrelated. We classified households into three groups based on how many orders per person per month they placed online: low (up to one), medium (more than once but less than four), and high (over four). We found that more e-shopping results in more household travel (number of trips, miles, and VMT), but this effect depends on e-shopping frequency and population density, and it affects weekdays more than weekends. E -shopping impacts household travel more for medium frequency e-shoppers in low density areas: compared to similar low frequency e-shoppers, on weekdays, they take on average 8 more monthly trips and travel ∼104 extra miles (including 31 miles for shopping). At the other end of the spectrum, high frequency e-shoppers in dense areas do not travel more on weekends than similar low e-shopping frequency households. To help reduce e-shopping induced travel, policymakers could encourage the creation of neighborhood depots where households would pick-up and return unwanted orders, and foster the development of virtual reality tools for shopping from home. • We analyze household travel data from the 2017 US National Household Travel Survey. • We use propensity score matching to infer causality between e-shopping and travel. • The impact on travel of e-shopping depends on its frequency and population density. • E-shopping increases household mileage most on weekdays and in low density areas. • There, mid-frequency e-shoppers travel ∼8 more weekday trips and 104 mi per month. [ABSTRACT FROM AUTHOR]

Background: Social media in scientific research offers a unique digital observatory of human behaviours and hence great opportunities to conduct research at large scale, answering complex sociodemographic questions. We focus on the identification and assessment of biases in social-media-administered surveys. Objective: This study aims to shed light on population, self-selection, and behavioural biases, empirically comparing the consistency between self-reported information collected traditionally versus social-media-administered questionnaires, including demographic and psychometric attributes. Methods: We engaged a demographically representative cohort of young adults in Italy (approximately 4,000 participants) in taking a traditionally administered online survey and then, after one year, we invited them to use our ad hoc Facebook application (988 accepted) where they filled in part of the initial survey. We assess the statistically significant differences indicating population, self-selection, and behavioural biases due to the different context in which the questionnaire is administered. Results: Our findings suggest that surveys administered on Facebook do not exhibit major biases with respect to traditionally administered surveys in terms of neither demographics nor personality traits. Loyalty, authority, and social binding values were higher in the Facebook platform, probably due to the platform's intrinsic social character. Conclusions: We conclude that Facebook apps are valid research tools for administering demographic and psychometric surveys, provided that the entailed biases are taken into consideration. Contribution: We contribute to the characterisation of Facebook apps as a valid scientific tool to administer demographic and psychometric surveys, and to the assessment of population, self-selection, and behavioural biases in the collected data.

Online reviews suffer from self-selection biases. One of these is under-reporting bias: those who have an extreme experience, either positive or negative, are more likely to review a product than those who have a moderate experience, and consequently are overrepresented in the sample of reviews. In this paper we study whether under-reporting bias decreases the effectiveness of the mean star-rating as a criterion for choosing between competing products of different but unobservable qualities. We formulate a model of consumer choice and the decision to review, and simulate this model in a variety of scenarios. We find that if under-reporting bias decreases the effectiveness of the mean star-rating, this is usually only for products that are of either extremely poor or extremely good quality. Even in these cases, the effectiveness is reduced only when the extent of bias is extreme and the variance in quality is low. Otherwise, the presence of under-reporting bias generally does not decrease, and in fact, often enhances the effectiveness of the mean star-rating as a measure of relative quality. [ABSTRACT FROM AUTHOR]

The overarching goal of nutrition labelling is to transform intrinsic credence attributes into searchable cues, which would enable consumers to make informed food choices at lower search costs. This study estimates the impact of nutrition label usage on Canadian consumers' ( n = 8,114) perceived diet-health concerns using alternative propensity score matching (PSM) techniques. We apply a series of tests and sensitivity analyses to overcome issues of endogeneity and selection bias frequently found in studies of diet-health behaviour and to validate the impact of exposure to nutrition facts labels for users vs. non-users. Our results support the notion that consumer uncertainty and related food-health concerns are linked to their information behaviour, but not in straightforward manner. Dominant subjective food attributes, such as taste, convenience and affordability, may in fact outweigh the benefits of information about healthier, alternative food choices. In order to change dietary health behaviour, food manufacturer and policy makers alike need to adopt communication instruments that better account for differences in preferences, shopping habits and overall usage patterns of nutrition labelling information. [ABSTRACT FROM AUTHOR]

A large number of microfinance impact assessment studies were conducted in different parts of the world in last two decades, but most of the impact assessment methods were put to questions. There were methodological concerns associated with both external validation and internal validation. Many microfinance impact assessment studies have suffered from issues related to counterfactual selection, project/programme placement bias and self-selection bias. To address those problems, this paper studied some of the important impact assessment frameworks. This study involved extensive literature scanning. Important impact assessment models were analysed and discussed focusing on unit of analysis, selection of impact variables, selection of comparison group and control of self-selection bias and project placement bias. The study concluded that a methodical analysis of counterfactual would help in avoiding self-selection bias and project placement bias. [ABSTRACT FROM AUTHOR]

Observational treatment studies provide a valuable alternative to RCTs but are often criticized due to potential self-selection biases. Studies comparing those who do and do not participate in research on eating disorder treatment are scarce, but necessary to evaluate the impact of self-selection bias on outcomes. All consecutive underweight adult first admissions ( N = 392) to an integrated inpatient (IP)-partial hospital (PH) behavioral specialty program were invited to participate in a longitudinal study of eating disorder treatment. Demographic and hospital course data were collected on participants ( n = 234) and non-participants ( n = 158). Participants and non-participants had similar BMI at admission, lengths of stay, and weight gain rates. Participants were less likely than non-participants to end treatment prematurely from IP and were discharged at a higher BMI; the effect size was small. Few differences in hospital course were observed between participants and non-participants. Although participants were more likely to transition to PH and were discharged at a higher BMI, completion of step-down to PH within this integrated IP-PH program rather than research participation status at admission was a better indicator of discharge BMI, which remains the strongest predictor of long-term weight-maintenance in eating disorders. [ABSTRACT FROM AUTHOR]

Background The objective of this study was to evaluate if mammography screening attendance is associated with a reduction in late-stage breast cancer incidence. Methods The cohort included over 400,000 Italian women who were first invited to participate in regional screening programmes during the 1990s and were followed for breast cancer incidence for 13 years. We obtained individual data on their exposure to screening and correlated this with total and stage-specific breast cancer incidence. Socio-economic status and pre-screening incidence data were used to assess the presence of self-selection bias. Results Overall, screening attendance was associated with a 10% excess risk of in situ and invasive breast cancer (IRR = 1.10; 95% confidence interval (CI): 1.06–1.14), which dropped to 5% for invasive cancers only (IRR = 1.05; 95% CI: 1.01–1.09). There were significant reductions among attenders for specific cancer stages; we observed a 39% reduction for T2 or larger (IRR = 0.61; 95% CI: 0.57–0.66), 19% for node positives (IRR = 0.81; 95% CI: 0.76–0.86) and 28% for stage II and higher (IRR = 0.72; 95% CI: 0.68–0.76). Our data suggest that the presence of self-selection bias is limited and, overall, invited women experienced a 17% reduction of advanced cancers compared with pre-screening rates. Conclusions Comparing attenders' and non-attenders' stage-specific breast cancer incidence, we have estimated that screening attendance is associated with a reduction of nearly 30% for stages II+. [ABSTRACT FROM AUTHOR]

The choice of irrigation water sources is crucial in rice farming as water availability and cost can vary across water sources. Groundwater caters three-quarters of the total irrigated land in Bangladesh, where rice area alone occupies 80% of the total irrigated land. The present study compares productivity and efficiency differences and determinants of surface and groundwater irrigation users based on a sample of 6947 dry-winter rice growing plots from the nationally representative Bangladesh Integrated Household Survey-2018 database. A range of methods was adopted to correct for heterogeneity in irrigation water source choice decision, self-selection and observable biases. This involved an estimation of a Stochastic Production Frontier (SPF) model with the pooled sample first, then an application of Propensity Score Matching (PSM) to remove self-selection and observable biases, then a test of heterogeneity in irrigation source choices was conducted, and finally estimated two SPF separately for matched samples of groundwater and surface water irrigation users. Results revealed a robust effect of groundwater irrigation in enhancing rice productivity and efficiency. Seed and its quality, fertilizer and soil type are also significant drivers of rice productivity. The significant drivers of efficiency are plot ownership, irrigation frequency, subsidy and family size. Large farms with groundwater-irrigated plots are relatively more efficient. Significantly lower efficiency exists in areas vulnerable to drought. These results raise sustainability concerns owing to the high level of groundwater extraction and falling water table. Policymakers need to devise innovative strategies to increase use of surface water irrigation without sacrificing productivity and efficiency, which has been a priority policy drive in Bangladesh. • Competitiveness of groundwater versus surface water for irrigation is evaluated. • Groundwater irrigation technology enhances rice productivity and efficiency. • Dominance of groundwater for irrigation raises environmental/sustainability concern. • Plot ownership, irrigation frequency, subsidy and family size drive efficiency. • Innovative strategies are required to encourage surface water irrigation technology. [ABSTRACT FROM AUTHOR]

Propensity score based methods applied to mitigate the bias in treatment effect estimation incurred by self-selection on observables, usually follow non-parametric matching approaches. Parametric estimation, performed by regressing solely on propensity scores, is suggested in theory, but is not generally applied. However, when appropriate, a parametric approach is preferable to a non-parametric or semi-parametric one as it provides more information, insight and inference on the same data set. We test parametric regression method through simulations, creating different scenarios of system-determined treatment assignment. It results that regressing only on propensity score, is not sufficient to properly mitigate the treatment estimation bias. We consider the propensity score as an omitted variable, which when added into the model, makes covariates and the binary treatment of interest conditionally independent. Propensity score enters the model as a generated regressor, because it is created in a separate modeling stage, and provides for unbiased and consistent estimation of treatment effects. This estimation is superior to the semi-parametric ones in our tests. Two real data with potential self-selection bias problems are analyzed to illustrate some application issues and to point out in particular the need for specific propensity scores application at any given situation. [ABSTRACT FROM AUTHOR]

In order to improve the rural labor productivity and farmers' income, land use transfer was launched and encouraged in recent years, especially the Thirteenth Five-Year Plan (2016-2020). This study aims to shed light on the impact of land use rights transfer on household labor productivity, based on a case study of Chongqing in China. Studies have revealed that land use transfer entails a process of self-selection and does not occur in a random manner. The study, therefore, addressed the issue of sample selection by applying propensity score matching. The study results suggested significant differences in the effects of land use transfer on household labor productivity. Specifically, renting land from other households had a positive effect on total labor productivity (TLP) and agricultural labor productivity (ALP). Moreover, TLP and ALP were found to be higher for households that rented more land or that were located in plain areas. Renting out land had a robust and positive effect on the TLP and non-agricultural labor productivity (NALP). TLP and NALP were also higher for households that rented out more land or that were located in plain areas. These findings suggest that land use transfer should be actively encouraged in plain areas. However, in mountainous areas, there is a need to pay more attention to expanding agriculture to benefit poor and marginalized populations in these areas. [ABSTRACT FROM AUTHOR]

Obtaining informed consent from individuals to participate in voluntary research studies is widely considered to be an ethical research practice. However, there is considerable debate over how consent should be obtained from subjects. Many researchers argue that active (opt-in) consent is the only type of consent that accurately reflects the true wishes of the subject and is closer to the informed consent ideal than passive (opt-out) consent procedures. Opponents of active consent procedures argue that such procedures harm study participation rates and increase the risk of self-selection bias to a greater extent than passive consent procedures. Empirical evaluations of these claims are rare, given the lack of studies that experimentally assign subjects to different consent procedures and utilize a control group (in which no consent is sought) to facilitate comparison. We report on an experiment that overcomes these issues in an study of consent to transfer contact data from a federal register to a third-party data collector for purposes of carrying out a telephone survey. Specifically, we evaluate the impact of requiring consent on survey participation rates, self-selection bias, and the resulting survey estimates. We find that the passive consent procedure does a better job of minimizing self-selection bias and maximizing the validity of the survey estimates (relative to the control group) compared with the active consent procedure. However, neither procedure is ideal: Both consent procedures increase the total self-selection bias and reduce the sample size. We conclude with a general discussion of the main findings and their practical implications. [ABSTRACT FROM AUTHOR]

In China, many rural migrant workers live in urbanising villages that are usually located in peripheral areas of major cities. Different from the spatial mismatch literature in which locations of minorities in the US are constrained by racial discrimination in the housing market, the residential segregation of rural migrant workers in China is largely due to China’s unique institutional context (e.g. land tenure system, hukou system) and the exclusionary housing regulations. Those living in these urbanising villages could incur both negative spatial mismatch effects and positive spillover effects. Through a survey across four mega-regions in China that are currently experiencing the most rapid urbanisation, we collect unique information on rural migrant workers’ attitudes towards living in urbanising villages, and therefore are able to address the self-selection bias that has broadly existed in many previous studies on residential segregation and spatial mismatch. The models show that the net effect of residential segregation in urbanising villages on migrant workers’ employment outcomes (both employment propensity and wage) appears to be positive, suggesting the spillover effects override the spatial mismatch effects. Current policy proposals by government officials to demolish urbanising villages should be accompanied by alternative policies to assist with housing migrant workers in appropriate locations that not only reduce spatial mismatch effects but also maintain positive spillover effects. [ABSTRACT FROM AUTHOR]

Scholars and planners have emphasized the importance of community spaces to enhance social capital in neighborhoods. This study extends the previous literature examining the influences of community centers on social capital in neighborhoods. Although prior research have estimated the association between community spaces uses and individual level of social capital, there is limited understanding of the causal direction of the effects of community spaces. This study fills this gap by employing the behavioral dissonance framework to clarify the effects of self-selection bias and/or actual effects of community center uses on social capital. Based on a household drop-off survey of 600 respondents in Seoul, Korea, we use a multiple regression model to identify the relationships between community center uses and overall social capital. Additionally, we take account of how the influences of community center use vary across different domains of social capital by employing ordinal logistic regression models. Our results may help planners and policymakers better understand how to enhance social capital with community spaces and develop tailored strategies to achieve social sustainability in regenerated neighborhoods according to different domains of social capital. • Explore the impacts of community center uses on social capital. • Specify how the impacts vary across different domains of social capital. • Employ the behavioral dissonance framework to clarify self-selection bias. • Community center use increases overall social capital. • Results vary across different domains of social capital and individual attitudes. [ABSTRACT FROM AUTHOR]

Understanding the relationships between influential factors and incident clearance time is crucial to make effective countermeasures for incident management agencies. Although there have been a certain number of achievements on incident clearance time modeling, limited effort is made to investigate the relative role of incident response time and its self-selection in influencing the clearance time. To fill this gap, this study uses the endogenous switching model to explore the influential factors in incident clearance time, and aims to disentangle causation from self-selection bias caused by response process. Under the joint two-stage model framework, the binary probit model and switching regression model are formulated for both incident response time and clearance time, respectively. Based on the freeway incident data collected in Washington State, full information maximum likelihood (FIML) method is utilized to estimate the endogenous switching model parameters. Significant factors affecting incident response time and clearance time can be identified, including incident, temporal, geographical, environmental, traffic and operational attributes. The estimate results reveal the influential effects of incident, temporal, geographical, environmental, traffic and operational factors on incident response time and clearance time. In addition, the causality of incident response time itself and its self-selection correction on incident clearance time are found to be indispensable. These findings suggest that the causal effect of response time on incident clearance time will be overestimated if the self-selection bias is not considered. [ABSTRACT FROM AUTHOR]

We examine the impacts of carsharing on travel behavior utilizing a San Francisco Area subsample of the 2010–2012 California Household Travel Survey. We control for self-selection bias due to differences in observed characteristics of the respondents using propensity-score based matching. We find that vehicle holdings of carsharing members are substantially and significantly lower than for non-members with similar characteristics in terms of individual and household demographics and built environment features of both residential and job location. These differences increase as the propensity to enroll in carsharing programs increases. A latent construct, which measures the propensity to own or utility from owning vehicles and rises with numbers of vehicles owned, is lower for members by 0.3–1.3 standard deviations relative to non-members. Members are also likely to walk, bike, and use transit more frequently than non-members. However, these differences are relatively minor and tend to be statistically non-significant. Future research should control for self-selection bias arising from differences in unobserved characteristics of respondents, as well as simultaneity bias whereby decisions concerning vehicle ownership both influence and are influenced by the decision to join carsharing programs. [ABSTRACT FROM AUTHOR]

All-red (AR) interval is designed as a method of clearance interval to safely clear vehicles that enter the signalized intersection. The provision of AR is generally expected to reduce the occurrence of crashes, though there are situations that AR is not proved to be effective because it is used at intersections with a higher potential for crashes. This controversial result however, does not indicate that the AR interval is a contributing cause of crashes. Therefore, the self-selection bias of signal designs needs to be corrected when estimating their effect in improving safety. To address the selection-bias problem at signalized intersections, a Heckman two-stage approach is adapted. First, a probit model is developed to explain the interrelationship between the AR interval and highway geometry, traffic volume and environmental variables. Second, the selection bias term (or Heckman correction) is included in the second stage to build two negative binomial models for locations with and without an AR interval. Three-year crash data on urban signalized intersections in the Detroit metro area is used to validate the proposed models. The results show that the impact of AR intervals is 51.7% reduction in total crashes on the treated intersections, and 42.5% on a random intersection. [ABSTRACT FROM PUBLISHER]

To promote regional economic development, China introduced regional development plans (RDPs) in 2009. This is the first study to investigate the net effect of the RDPs on China's regional economic growth by employing the multi-stage difference-in-differences (DID) strategy and a city-level panel data set during the 2004–2015 period. We reduce the self-selection bias by employing the propensity score matching strategy and explore the mediating effects from two perspectives, i.e., investment scale and production efficiency. Finally, using nighttime satellite light data, we conduct a robustness test of the previous results. The results show that the RDPs have a significant negative impact on economic growth, with strong regional heterogeneity. The RDPs have no effect on economic growth in western cities when reducing self-selection bias, and the underlying reason is that their impacts on both the investment scale and production efficiency are unclear. However, the RDPs exert significantly negative impacts on economic growth in the eastern and central regions. The negative impacts are mainly because the RDPs decrease production efficiency to inhibit economic growth. Therefore, the central government needs to attach great importance to the improvement of the production efficiency when regulating regional development. • The effect of the Regional Development Plans (RDPs) on economic growth is investigated. • The self-selection effects and mediating mechanisms are also discussed. • The RDPs has a significant negative impact on economic growth. • The RDPs' impacts show clear geographical differences. • The negative impact occurred mainly because the RDPs decreased production technological efficiency. [ABSTRACT FROM AUTHOR]

Agri-environment schemes (AESs) have been developed by governments to improve biodiversity, reduce pollution from farming and encourage the provision of agriculture's non-market benefits. Despite the substantial amount of money spent on designing, implementing and monitoring AESs, their environmental effectiveness is ambiguous. The objective of this paper is to investigate the relationship between farmer participation in an AES and the quantity and quality of semi-natural habitats found on farms. This study combines socio-economic survey data from Irish farms in 2012 with farmland habitat data collected in 2015–16 from a subset of participating farms in the original 2012 socio-economic survey. Given the voluntary nature of AESs, a matching technique is applied to control for self-selection bias and test whether farmer participation in an AES is related to the quantity and quality of habitats found on Irish farms. Although farmer participation in an AES is found to be positively related to habitat quantity and quality, we are unable to reject the null hypothesis of no statistically significant differences between habitat quantity and quality of participants in an AES and non-participants. However, results highlight that the share of habitat area (proxy variable for habitat quantity) varies significantly across farm households with different socio-economic characteristics, soil type, farm structures and location. Future policies could scale up the implementation of outcome-based payments or market-based instruments to incentivize farmers in improving their environmental performance. However, such policy improvements would still require the development of robust and transparent monitoring mechanisms. • Participation in an AES is positively related to habitat quantity and quality. However, these relationships are statistically non-significant. • The share of habitat area varies across farm households with different socio-economic characteristics, soil type, farm structure and location. • Policies could scale up the implementation of results-based payments to incentivize farmers in improving their environmental performance. [ABSTRACT FROM AUTHOR]

Estimates of the effect of employment on women’s risk of partner violence in cross-sectional studies are subject to potential “self-selection bias.” Women’s personal choice of whether to pursue employment or not may create fundamental differences between the group of women who are employed and those who are not employed that standard regression methods cannot account for even after adjusting for confounding. The aim of this study is to demonstrate the utility of propensity score matching (PSM), a technique used widely in econometrics, to address this bias in cross-sectional studies. We use PSM to estimate an unbiased effect-size of women’s employment on their risk of experiencing partner violence in urban and rural Tanzania using data from the 2010 Tanzania Demographic and Health Survey (DHS). Three different measures of women’s employment were analyzed: whether they had engaged in any productive work outside of the home in the past year, whether they received payment in cash for this productive work, and whether their employment was stable. Women who worked outside of the home were significantly different from those who did not. In both urban and rural Tanzania, women’s risk of violence appears higher among women who worked in the past year than among those who did not, even after using PSM to account for underlying differences in these two groups of women. Being paid in cash reversed this effect in rural areas whereas stability of employment reduced this risk in urban centers. The estimated size of effect varied by type of matching estimator, but the direction of the association remained largely consistent. This study’s findings suggest substantial self-selection into employment. PSM methods, by compensating for this bias, appear to be a useful tool for estimating the relationship between women’s employment and partner violence in cross-sectional studies. [ABSTRACT FROM AUTHOR]

As part of a large sexual health study, we used two different approaches to target Sexual Minority Individuals (SMIs). Firstly, we drew on a probability sample (1,832 respondents aged 14-80) of the Flemish population in Belgium. Secondly, we set up a targeted sampling design followed by an Internet survey. Our focus was to explore how two different sampling procedures and survey designs could lead to differences in sample characteristics. Results showed that for female SMIs (we excluded male SMIs from the analyses due to their low numbers) the population sample differed from the Internet sample in terms of sociodemographic characteristics (the latter included younger and more highly educated respondents) and scores on sexual orientation dimensions (the population sample included more respondents who didn't identify as lesbian or bisexual but reported same-sex sexual experiences and desire). Respondents' scores on sexual health indicators differed between the samples for two of the seven variables. We discuss implications for improving the quality and validity of nonrandom samples. [ABSTRACT FROM AUTHOR]

The aim of this study was to look at the issue of nonresponse and self-selection bias in the context of a family study on daily family life. Data on the participating families and refusers were gathered as part of the wider Palette study in which questionnaires and diaries were used as data collection methods. On the basis of these data (N = 208 participating families and 119 refuser families), we profile the families left outside the study. The parents who declined to participate in the Palette study were asked to fill in a short refusal form, which included questions concerning their family background and reasons for refusal, and they were also asked to write freely about their everyday life. We found the refuser families to have less-educated mothers and more children than the participating families. On the basis of a qualitative analysis, three life situations which refusers considered too demanding to allow participation in the study were found. The challenges of reaching nonparticipants and the generalizability of the findings are discussed. [ABSTRACT FROM AUTHOR]

Abstract: This paper empirically evaluates the treatment effect of de facto pegged regimes on the occurrence of currency crises. To estimate the treatment effect of pegged regimes properly, we must carefully control for the self-selection problem of regime adoption because a country's exchange rate regime choice is nonrandom. To address the self-selection problem, we thus employ a variety of matching methods. We find interesting and robust evidence that (1) pegged regimes significantly decrease the likelihood of currency crises compared with floating regimes, and (2) pegged regimes with capital account liberalization significantly lower the likelihood of currency crises compared with other regimes. From the standpoint of the macroeconomic policy trilemma, we can reasonably conclude that pegged regimes with capital account liberalization are substantially less prone to speculative attacks because they can enhance greater credibility in their currencies by maintaining strict discipline for monetary and macroeconomic policies. [Copyright &y& Elsevier]

IntroductionDelusions are typically characterised by idiosyncratic, self-generated explanations used to interpret events, as opposed to the culturally normative interpretations. Thus, a bias in favour of one's own hypotheses may be a fundamental aspect of delusions. MethodsWe tested this possibility in the current study by comparing judgements of self-selected hypotheses to judgements of externally selected ones in a probabilistic reasoning task. This allowed us to equate self- and externally selected hypotheses in terms of objectively quantifiable supporting evidence. It is normal to be biased in favour of self-selected hypotheses, but we expected this bias to be exacerbated in schizophrenia patients relative to healthy and psychiatric controls, and to be correlated with the severity of delusions in the schizophrenia sample. ResultsAs expected, all groups showed the self-selection bias. Although this bias was not increased in schizophrenia patients relative to the control groups, it was significantly correlated with the severity of delusions in the schizophrenia sample. ConclusionsThese results fit with an account holding that the hypersalience of an individual's own interpretations of events, relative to culturally normative interpretations, may manifest in a self-selection bias, contributing to the delusional state in schizophrenia. [ABSTRACT FROM PUBLISHER]

MagriniM.-B. and LemistreP. Distance–income migration trade-off of young French workers: an analysis per education level,Regional Studies. Most research studies on migration see the latter as a move from one geographic area to another. Taking into account distance in an analysis of young French workers' migration from one local labour market to another enables one to evaluate more precisely the migration decision, viewed as a cost–benefit trade-off based on the distance travelled and some territorial characteristics. It is found that the wage returns to migration are nil for the most highly skilled workers, leading one to consider that these workers conduct their job search on a national scale. In contrast, the less-skilled workers get a positive return to migration. MagriniM.-B. and LemistreP. ???????????????????????????????????? ????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ?????????????????????????????????????? MagriniM.-B. et LemistreP. L'arbitrage distance-revenu dans la décision de migration des jeunes travailleurs français: une analyse selon le niveau de l'éducation,Regional Studies. La plupart des études sur la migration s'intéresse au changement d'espaces géographiques. La prise en compte conjointe de la distance dans le changement de marché local de travail de jeunes travailleurs français, nous permet ici d'évaluer plus précisément la décision de migration, considérée comme un arbitrage coûts-avantages fondé sur la distance parcourue et des caractéristiques territoriales. Nous observons alors que les avantages salariaux liés à la migration sont nuls pour les plus qualifiés, ce qui nous conduit à considérer que ces travailleurs réalisent leur prospection d'emploi à l'échelle nationale. Tandis que les travailleurs les moins qualifiés obtiennent un rendement positif de la migration. Marché local du travail?Mobilité spatiale?Rendement salarial de la migration?Biais de sélection?Distance?Insertion professionnelle MagriniM.-B. und LemistreP. Abwägung von Entfernung und Einkommen bei der Migration junger französischer Arbeitnehmer: eine Analyse nach Bildungsebenen,Regional Studies. In den meisten Forschungsstudien wird die Migration als Umzug von einem geografischen Gebiet in ein anderes betrachtet. Die Berücksichtigung der Entfernung bei der Analyse der Migration von jungen französischen Arbeitnehmern von einem lokalen Arbeitsmarkt zu einem anderen ermöglicht eine präzisere Untersuchung der Migrationsentscheidung, die als Abwägung von Kosten und Nutzen aufgrund der zurückgelegten Entfernung und bestimmter territorialer Eigenschaften betrachtet wird. Wir stellen fest, dass sich der Lohnertrag der Migration bei den am höchsten qualifizierten Arbeitnehmern auf Null beläuft, was darauf schließen lässt, dass diese Arbeitnehmer ihre Arbeitssuche auf nationaler Ebene durchführen. Bei weniger qualifizierten Arbeitnehmern ist die Migration hingegen mit einem positiven Ertrag verbunden. Lokale Arbeitsmärkte?Räumliche Mobilität?Migrationsbedingter Lohnertrag?Verzerrung durch Selbstauswahl?Entfernung?Eintritt in Arbeitsmarkt MagriniM.-B. y LemistreP. Ponderación de la distancia y los ingresos en el contexto de la emigración de trabajadores franceses jóvenes: un análisis por nivel educativo,Regional Studies. En la mayoría de estudios se analiza la emigración como un desplazamiento de un espacio geográfico a otro. Al tener en cuenta la distancia en el análisis de la emigración de trabajadores franceses jóvenes de un mercado laboral local a otro, podemos valorar de forma más exacta la decisión de las emigraciones, considerando la relación coste-beneficio y basándonos en la distancia viajada y algunas características territoriales. Observamos que la rentabilidad salarial con respecto a la emigración es nula para los trabajadores mejor cualificados, lo que nos lleva a considerar que estos trabajadores buscan su trabajo a escala nacional. En cambio, los trabajadores menos cualificados obtienen una rentabilidad positiva de la emigración. Mercados laborales locales?Movilidad espacial?Rentabilidad salarial de la migración?Sesgo de autoselección?Distancia?Acceso al mercado de trabajo [ABSTRACT FROM PUBLISHER]

Abstract: This paper argues that wasted votes in founding elections decrease when countries have a previous democratic experience before the current democratic period. This historical-institutionalist argument is tested with national election results in 22 founding elections in third-wave European, Asian, Latin American and African democracies. The results demonstrate that having a democratic past clearly increases coordination and then reduces the percentage of wasted votes in the founding election, controlling for the electoral system. [Copyright &y& Elsevier]

The main goal of this study is to examine the effects of adoption disclosure on the adaptation of Korean adoptive families using a two stage equation model. The results of this study indicate that there is a self-selection bias between disclosed and closed adoptive families. Yet, even after considering this selection bias, adoption disclosure was associated with the positive outcomes of adoptive families. Also, the estimates in the treatment effect model were found to be very similar to those of the regression model, indicating that the degree of self-selection bias between these groups was not so strong as to distort the effects of adoption disclosure and other predictors. [ABSTRACT FROM AUTHOR]

The paper examines determinants of electoral entry and success of ethnic minority parties in central and eastern Europe. The application of a hierarchical selection model shows that the strategic entry of minority parties depends on their expected electoral success due both to observed and unobserved factors. Drawing on formal models of electoral entry, the electoral success of new (or niche) parties is expected to be influenced by the costs of entry (determined by electoral thresholds) and the potential for electoral support. The latter depends on the reactions of political competitors and electoral demand, measured here as the size of ethnic groups and the saliency of ethnic issues. In line with these expectations, parties only run if they can expect electoral support sufficient to pass the electoral threshold. This finding would have been overlooked by a naïve model of electoral success which does not take self-selection into account. [Copyright &y& Elsevier]