The validity of violence risk estimates: An issue of item performance.

Typically, research conducted on the cross-validation or generalization of risk assessment schemes focuses on the aggregate score accuracy of the schemes within the new sample or population. Often overlooked when the schemes are examined in their aggregate form is the performance of the individual items. This study looks at the association between the items of the HCR-20 (C. D. Webster, K. S. Eaves, D. Douglas, & S. D. Wintrup, 1995) and the Violence Risk Appraisal Guide (VRAG; C. D. Webster, G. T. Harris, M. E. Rice, C. Cormier, & V. L. Quinsey, 1994) and violent recidivism in a sample of predominantly violent offenders. The results show that a number of the items from each scale do not distinguish between violent recidivists and nonrecidivists and that the presence of these items potentially reduces the predictive accuracy of the instruments. In addition, the inclusion of items that do not discriminate between recidivists and nonrecidivists potentially undermines the validity of the risk assessment process. Discussion centers on the application of prediction schemes and their individual risk factors in forensic practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)