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.     

Normes,théorie des jeux et pratiques participatives: le poids réel des travailleurs dans les économies libérales

Les auteurs analysent l'effet de la directive européenne relative à l'information et à la consultation des travailleurs sur les pratiques participatives en entreprise au Royaume‐Uni et en Irlande. Dans une analyse conceptuelle et empirique, qui fait appel à la théorie des jeux, ils formulent trois hypothèses explicatives, qu'ils cherchent à vérifier avec des données qualitatives recueillies auprès de seize entreprises. La démonstration permet de comprendre pourquoi la coopération, gage de gains mutuels, n'est pas la solution qui l'emporte dans les pays examinés, et elle nous en dit un peu plus sur l'effet des normes sur la gestion participative dans les économies de marché libérales.     

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.     

Why combatants fight: the Irish Republican Army and the Bosnian Serb Army compared

This article investigates what motivates combatants to fight in non-conventional armed organizations. Drawing on interviews with ex-combatants from the Army of the Serbian Republic in Bosnia and Herzegovina and the Provisional Irish Republican Army, the article compares the role of nationalist ideology, coercive organizational structures, and small group solidarity in these two organizations. Our analysis indicates that coercion played a limited role in both armed forces: in the VRS coercion was relevant mostly in the recruitment phase, while in the IRA its direct impact was only discernible during armed operations. We also find that although both organizations are seen as being highly motivated by nationalist ideas, the picture is much more complex and nationalism is less present than expected. The study demonstrates that nationalism played a relatively marginal role in combatants’ motivation to fight. Instead our research indicates that individualist motivations, small group solidarity, and local networks dominate.     

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.