A Classification Tree Approach to the Development of Actuarial Violence Risk Assessment Tools

Since the 1970s, a wide body of research has suggested that the accuracy of clinical risk assessments of violence might be increased if clinicians used actuarial tools. Despite considerable progress in recent years in the development of such tools for violence risk assessment, they remain primarily research instruments, largely ignored in daily clinical practice. We argue that because most existing actuarial tools are based on a main effects regression approach, they do not adequately reflect the contingent nature of the clinical assessment processes. To enhance the use of actuarial violence risk assessment tools, we propose a classification tree rather than a main effects regression approach. In addition, we suggest that by employing two decision thresholds for identifying high- and low-risk cases--instead of the standard single threshold--the use of actuarial tools to make dichotomous risk classification decisions may be further enhanced. These claims are supported with empirical data from the MacArthur Violence Risk Assessment Study.     

Rejoinder to comments by Frederick Kaijage,Oswald Masebo,and Innocent Pikirayi on the keynote speech, ‘writing history: flow and blockage in the circulation of knowledge’

ABSTRACT

Rejoinder to comments by Frederick Kaijage, Oswald Masebo, and Innocent Pikirayi on the keynote speech, ‘Writing History: Flow and Blockage in the Circulation of Knowledge’     

The “dark figure” and composite indexes of crime: Some empirical explorations of alternative data sources

This paper compares composite crime indexes across two alternative data sources—the Uniform Crime Reports (UCR) and the National Crime Survey (NCS). A variety of indexes are constructed based on weights derived from Sellin and Wolfgang's “seriousness” scale. The results reveal that indexes weighted by offense seriousness are not very highly correlated across data sources for a sample of twenty-six American cities. The substantive importance of the discrepancies between UCR and NCS estimates is illustrated by examining the ecological correlates of weighted crime rates for the twenty-six city sample and by assessing changes in weighted crime rates at the national level for the 1973-81 period. The results also reveal that if estimates of homecide are included in the composite indexes by supplementing the NCS data with data from the Center for Health Statistics, then under certain weighting conditions the correlations across data sources are nearly perfect. The paper concludes with a discussion of the implications of this latter finding for the measurement of overall levels of criminal activity and for the scaling of the relative gravity of different offenses.     

Expanded School Mental Health: Challenges and Opportunities in an Emerging Field

Reviews the need for and development of expanded school mental health (ESMH) programs, which provide a continuum of mental health promotion and intervention through school–community partnerships. Since ESMH is a relatively new, but increasingly prominent field, countless issues are being addressed in practice and research and in efforts to bridge practice and research. We review particular content and context dimensions of ESMH in need of development including quality assessment and improvement, empirically supported practice, improving assessment and outcome evaluation, involving educators in the work, understanding school environments, and tailoring programs through qualitative research. Summaries of articles that amplify these themes are provided.     

A Re-examination of the Effects of Biased Lineup Instructions in Eyewitness Identification

A meta-analytic review of research comparing biased and unbiased instructions in eyewitness identification experiments showed an asymmetry; specifically, that biased instructions led to a large and consistent decrease in accuracy in target-absent lineups, but produced inconsistent results for target-present lineups, with an average effect size near zero (Steblay, 1997). The results for target-present lineups are surprising, and are inconsistent with statistical decision theories (i.e., Green & Swets, 1966). A re-examination of the relevant studies and the meta-analysis of those studies shows clear evidence that correct identification rates do increase with biased lineup instructions, and that biased witnesses make correct identifications at a rate considerably above chance. Implications for theory, as well as police procedure and policy, are discussed.