On a Dualization of Graphical Gaussian Models: A Correction Note

Abstract.  We correct two proofs concerning Markov properties for graphs representing marginal independence relations.     

Risk Compensation or Risk Reduction? Seatbelts,State Laws,and Traffic Fatalities*

Objective. The risk compensation hypothesis suggests that drivers enjoying greater safety will drive more recklessly and thereby impose greater risks on nonoccupants. We provide a test of the risk compensation hypothesis in the context of state seatbelt laws and belt use rates. Methods. Fixed‐effects models with policy and demographic variables are estimated using annual state data from 1985 to 2002 to test the effect of seatbelt laws and seatbelt use rates on logged fatality rates for occupants, pedestrians, motorcyclists, and all nonoccupants in separate models. Results. Contrary to the risk compensation hypothesis, the results indicate that both occupants and nonoccupants enjoy greater safety due to state mandatory use laws and increased safety belt use rates. Conclusion. Overall, seatbelt laws and the higher belt use these laws induce do not increase nonoccupant risk exposure. If anything, these laws and the accompanying increase in belt use result in safer driving behavior.     

Mandatory seat belt laws in the states. A study of fatal and severe occupant injuries

This study examines the impact of mandatory seat belt laws on fatal and incapacitating injury rates in the states. Annual data for all 50 states for the period 1975-1991 are used. Pooled time series analysis is employed. The general conclusion that emerges from this analysis is that seat belt laws significantly impact state fatal injury rates. Primary enforcement and all-seat coverage provisions appear to be particularly effective in reducing fatality rates.     

Job Search: A Multidisciplinary Review and Research Agenda

Scholarly interest in job search has grown significantly over the years and can be located in diverse research streams: namely, economics, sociology and industrial/organizational psychology. This paper reviews these bodies of literature and makes a case for integration by proposing a multidisciplinary approach to understanding job‐seeking behaviors. To this end, the paper categorizes the respective literatures on the basis of common themes located in a conceptual multidisciplinary model of job search behaviors and outcomes. This model provides a more focused understanding of the job search literature and how it has developed in the related disciplines. Based on the review and conceptual model presented, the paper draws attention to several key areas for future research to advance the field further.     

Introductory Statistics Textbooks and the GAISE Recommendations

The six recommendations made by the Guidelines for Assessment and Instruction in Statistics Education (GAISE) committee were first communicated in 2005 and more formally in 2010. In this article, 25 introductory statistics textbooks are examined to assess how well these textbooks have incorporated the three GAISE recommendations most relevant to implementation in textbooks (statistical literacy and thinking; use of real data; stress concepts over procedures). The implementation of another recommendation (using technology) is described but not assessed. In general, most textbooks appear to be adopting the GAISE recommendations reasonably well in both exposition and exercises. The textbooks are particularly adept at using real data, using real data well, and promoting statistical literacy. Textbooks are less adept—but still rated reasonably well, in general—at explaining concepts over procedures and promoting statistical thinking. In contrast, few textbooks have easy-usable glossaries of statistical terms to assist with understanding of statistical language and literacy development. Supplementary materials for this article are available online.     

The Importance of Racial Socialization: School‐Based Racial Discrimination and Racial Identity Among African American Adolescent Boys and Girls

This study examined various parental racial socialization messages as mediators between school‐based racial discrimination and racial identity formation over 4 years for African American boys (N = 639) and African American girls (N = 711). Findings indicated that school‐based racial discrimination was associated with racial identity beliefs. For African American boys, behavioral racial socialization messages mediated the relation between school‐based racial discrimination and racial centrality over time. Mediation also resulted for African American girls, but for a different set of race‐related messages (negative messages and racial barriers) and racial identity beliefs. The developmental significance of the findings and implications for future research are discussed.     

Using Bayesian graphical models to model biases in observational studies and to combine multiple sources of data: application to low birth weight and water disinfection by-products

Summary.  Data in the social, behavioural and health sciences frequently come from observational studies instead of controlled experiments. In addition to random errors, observational data typically contain additional sources of uncertainty such as missing values, unmeasured confounders and selection biases. Also, the research question is often different from that which a particular source of data was designed to answer, and so not all relevant variables are measured. As a result, multiple sources of data are often necessary to identify the biases and to inform about different aspects of the research question. Bayesian graphical models provide a coherent way to connect a series of local submodels, based on different data sets, into a global unified analysis. We present a unified modelling framework that will account for multiple biases simultaneously and give more accurate parameter estimates than standard approaches. We illustrate our approach by analysing data from a study of water disinfection by-products and adverse birth outcomes in the UK.     

Applying a Positive Youth Development Perspective to Observation of Bereavement Camps for Children and Adolescents

A positive youth development perspective focuses on recognizing psychosocial strengths and providing social environments that contribute to the development of these in children and adolescents. Bereavement camps can provide such an environment as they help children cope with the death of someone close. The purpose of this study was to observe bereavement camps through the lens of positive youth development to determine the applicability of the eight features of positive developmental settings for describing bereavement camps (safety, appropriate structure, supportive relationships, opportunities to belong, positive norms, support for efficacy, skill building opportunities, integration of family and community). Observational notes were recorded by researchers during on-site visits to three different weekend bereavement camps. Results identified how each element of positive developmental settings was exemplified in either typical camp activities or bereavement-focused activities. For example, assigning campers to cabin groups based on age and gender provided opportunities to belong, and giving campers a comfort object and a big buddy provided supportive relationships. Findings were used to create a positive developmental settings observation checklist for use by bereavement camp practitioners to assess the extent to which each camp provides the requisite elements for promoting positive youth development.