A Bayesian Multilevel Modeling Approach to Time-Series Cross-Sectional Data

Joseph Bafumi Department of Government, Dartmouth College,6108 Silsby HallHanover, NH 03755 e-mail: joseph.bafumi{at}dartmouth.edu Luke Keele Department of Political Science, Ohio State University,2137 Derby Hall, 154 N Oval Mall, Columbus, OH 43210 e-mail: keele.4{at}polisci.osu.edu David Park Department of Political Science, George Washington University,1922 F Street, N.W. 414C, Washington, DC 20052 e-mail: dkp{at}gwu.edu e-mail: bshor{at}uchicago.edu (corresponding author) The analysis of time-series cross-sectional (TSCS) data hasbecome increasingly popular in political science. Meanwhile,political scientists are also becoming more interested in theuse of multilevel models (MLM). However, little work existsto understand the benefits of multilevel modeling when appliedto TSCS data. We employ Monte Carlo simulations to benchmarkthe performance of a Bayesian multilevel model for TSCS data.We find that the MLM performs as well or better than other commonestimators for such data. Most importantly, the MLM is moregeneral and offers researchers additional advantages. Authors' note: A previous version of this article was presentedat the 2005 Midwest Political Science Meeting. We would liketo thank the following for comments and advice in writing thispaper: Andrew Gelman, Nathaniel Beck, Greg Wawro, Sam Cooke,John Londregan, David Brandt. Any errors are our own.     

Cautioning jurors regarding co-witness discussion: the impact of judicial warnings

Abstract

The research seeks to identify the most common problem areas and associated treatment needs of incarcerated and recently released offenders, to determine the importance of prison-based treatment and to assess the motivation of offenders towards treatment. Interviews were scheduled with representatives of three participant categories: drug-involved incarcerated offenders (n=18), recently released prisoners (n=15) and treatment staff members (n=18), resulting in 1971 statements. Using the qualitative software package WinMAX98, these expressions were categorized in a tree structure, after a codification process of the raw material. The results suggest that there is a difference in opinion between offenders and service providers with regard to the most important problems related to incarceration and re-entry. The findings further indicate that released offenders struggle more often than incarcerated offenders with problems concerning their psychological status. Therefore, the need for continuous through-care and aftercare is apparent, as is the necessity to assess the participants’ support expectancies and their individual needs. Motivating offenders to take part in (prison-based) treatment initiatives and aftercare is a major challenge, which can be accomplished by cooperation and partnerships between the criminal justice system and community-based treatment providers.     

Investigating the relationship between justice‐vengeance motivations and punitive sentencing recommendations

Purpose. The present research investigated the relationship between underlying justice and vengeance motivations and sentencing recommendations made by expert clinicians, semi‐experts, and lay‐people. It was hypothesized that the semi‐experts would recommend significantly different sentence lengths from those recommended by the expert and lay‐person groups, in line with previous research findings. It was also hypothesized that justice and vengeance motivations would be related to punitive sentencing recommendations, and that these would not be the same across the three levels of expertise. Method. An independent groups design was utilized in the main analysis, with participants belonging to three distinct levels of clinical experience (experts, semi‐experts, and lay‐people). A questionnaire was administered, with participants being measured on levels of justice and vengeance motivations, and asked to recommend appropriate sentence lengths based on nine separate crime‐scenarios. These covariables were correlated and the correlation coefficients were compared across the three levels of expertise. Results. The former hypothesis was not upheld. Findings do, however, support the latter hypothesis, with the key finding indicating that for both justice and vengeance motivations in punitive judgement, it is the lay‐participants who appear distinct from the experts and semi‐experts. Conclusions. The current findings emphasize that while expert and lay‐person judgements may often appear to be the same, different processes and motivations underlying clinical judgements are occurring at the different stages of expertise. With the differences in the relationships between justice and vengeance motivations and judgements found in the current research, it is argued that expert and lay judgements that appear to be the same are, in fact, distinguishable and are related to quite different underlying motivations and decision‐making processes.     

Medical professionals convicted of accessing child pornography--presumptive lifetime prohibition on paediatric practice? Health Care Complaints Commission v Wingate

Health Care Complaints Commission v Wingate [2007] NSWCA 326 concerns an appeal from the New South Wales Medical Tribunal regarding its findings on professional misconduct outside the practice of medicine in relation to a doctor convicted of possessing child pornography. The latest in a number of cases on this issue in Australia, it highlights the complexity of such decisions before medical tribunals and boards, as well as the diversity of approaches taken. Considering both this case and the recent Medical Practitioners Board of Victoria case of Re Stephanopoulos [2006] MPBV 12, this column argues that Australian tribunals and medical boards may not yet have achieved the right balance here in terms of protecting public safety and the reputation of the profession as a whole. It makes the case for a position statement from Australian professional bodies to create a presumption of a lifetime prohibition on paediatric practice after a medical professional has been convicted of accessing child pornography.     

Strengthening the Experimenter’s Toolbox: Statistical Estimation of Internal Validity

Experiments have become an increasingly common tool for political science researchers over the last decade, particularly laboratory experiments performed on small convenience samples. We argue that the standard normal theory statistical paradigm used in political science fails to meet the needs of these experimenters and outline an alternative approach to statistical inference based on randomization of the treatment. The randomization inference approach not only provides direct estimation of the experimenter’s quantity of interest—the certainty of the causal inference about the observed units—but also helps to deal with other challenges of small samples. We offer an introduction to the logic of randomization inference, a brief overview of its technical details, and guidance for political science experimenters about making analytic choices within the randomization inference framework. Finally, we reanalyze data from two political science experiments using randomization tests to illustrate the inferential differences that choosing a randomization inference approach can make.     

Dynamic Models for Dynamic Theories: The Ins and Outs of Lagged Dependent Variables

Nathan J. Kelly Department of Political Science, University of Tennessee, 1001 McClung Tower, Knoxville, TN 37996-0410 e-mail: luke.keele{at}mail.polisci.ohio-state.edu (corresponding author) e-mail: nathan.j.kelly{at}gmail.com A lagged dependent variable in an OLS regression is often usedas a means of capturing dynamic effects in political processesand as a method for ridding the model of autocorrelation. Butrecent work contends that the lagged dependent variable specificationis too problematic for use in most situations. More specifically,if residual autocorrelation is present, the lagged dependentvariable causes the coefficients for explanatory variables tobe biased downward. We use a Monte Carlo analysis to assessempirically how much bias is present when a lagged dependentvariable is used under a wide variety of circumstances. In ouranalysis, we compare the performance of the lagged dependentvariable model to several other time series models. We showthat while the lagged dependent variable is inappropriate insome circumstances, it remains an appropriate model for thedynamic theories often tested by applied analysts. From theanalysis, we develop several practical suggestions on when andhow to use lagged dependent variables on the right-hand sideof a model.     

Civic Engagements: Resolute Partisanship or Reflective Deliberation

Why do people practice citizenship in a partisan rather than in a deliberative fashion? We argue that they are not intractably disposed to one type of citizenship, but instead adopt one of two different modes depending on the strategic character of current circumstances. While some situations prompt partisan solidarity, other situations encourage people to engage in open‐minded deliberation. We argue that the type of citizenship practiced depends on the engagement of the emotions of anxiety and aversion. Recurring conflict with familiar foes over familiar issues evokes aversion. These angry reactions prepare people for the defense of convictions, solidarity with allies, and opposition to accommodation. Unfamiliar circumstances generate anxiety. Rather than defend priors, this anxiety promotes the consideration of opposing viewpoints and a willingness to compromise. In this way, emotions help people negotiate politics and regulate the kinds of citizenship they practice.