Race,Neighborhood Disadvantage,and Violence Among Persons with Mental Disorders: The Importance of Contextual Measurement

The individualistic fallacy (i.e., the fallacy of assuming that individual-level outcomes can be explained exclusively in terms of individual-level characteristics) is a problem with most research on violence, and is particularly problematic in research on mental disorder and violence. This article illustrates the importance of measuring community context by showing that race is not an important predictor of violence among persons with mental disorders when neighborhood disadvantage is controlled statistically. More generally, these results suggest that researchers run the risk of perpetuating the individualistic fallacy in studies of violence by persons with mental disorders when they use individual-level risk factors as predictors, but do not control for community context.     

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.