Discrimination and Calibration Properties of the Violence Risk Appraisal Guide-Revised in a Not Criminally Responsible Provincial Population.

Abstract

This study examined the discrimination and calibration properties of the Violence Risk Appraisal Guide-Revised (VRAG-R) within a large subset of the population of 574 individuals who had been found Not Criminally Responsible on Account of Mental Disorder (NCRMD) in Alberta. The VRAG-R was scored on all individuals identified via The Alberta NCR Project database from every file that contained sufficient relevant information and recidivism data were obtained via official criminal records. The VRAG-R demonstrated strong discrimination properties for general and violent recidivism over 5-year, 10-year, and global follow-ups. Calibration analyses, however, indicated that the VRAG-R substantially over estimated violence risk and that there was poor agreement between expected and observed recidivism rates for this population. When examined in the male subsample, these issues remained but to a lesser degree; examination of VRAG-R discrimination and calibration for females was not possible due to a lack of recidivists. Results indicated strong discrimination but poor calibration properties of the VRAG-R in this NCRMD population. Overall, the results support the use of the VRAG-R within a population of persons found NCRMD when employed in tandem with other measures as part of a comprehensive psychological risk assessment.