Special Issue Article
Another Look at the (Im-)Precision of Individual Risk Estimates Made Using Actuarial Risk Assessment Instruments
Version of Record online: 16 JAN 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Behavioral Sciences & the Law
Special Issue: Methodological Issues in Measuring and Interpreting the Predictive Validity of Violence Risk Assessments
Volume 31, Issue 1, pages 81–102, January/February 2013
How to Cite
Hart, S. D. and Cooke, D. J. (2013), Another Look at the (Im-)Precision of Individual Risk Estimates Made Using Actuarial Risk Assessment Instruments. Behav. Sci. Law, 31: 81–102. doi: 10.1002/bsl.2049
- Issue online: 26 FEB 2013
- Version of Record online: 16 JAN 2013
- Manuscript Accepted: 19 NOV 2012
- Manuscript Revised: 14 NOV 2012
- Manuscript Received: 22 JUL 2012
- British Columbia Forensic Psychiatric Services Commission
We investigated the precision of individual risk estimates made using actuarial risk assessment instruments (ARAIs) by discussing some major conceptual issues and then illustrating them by analyzing new data. We used a standard multivariate statistical procedure, logistic regression, to create a new ARAI based on data from a follow-up study of 90 adult male sex offenders. We indexed predictive precision at the group level using confidence intervals for group mean probability estimates, and at the individual level using prediction intervals for individual probability estimates. Consistent with past research, ARAI scores were moderately and significantly predictive of failure in the aggregate, but group probability estimates had substantial margins of error and individual probability estimates had very large margins of error. We conclude that, without major advances in our understanding of the causes of violence, ARAIs cannot be used to estimate the specific probability or absolute likelihood of future violence with any reasonable degree of precision or certainty. The implications for conducting violence risk assessments in forensic mental health are discussed. Copyright © 2013 John Wiley & Sons, Ltd.