When sex offenders in Minnesota are assigned risk levels prior to their release from prison, correctional staff frequently exercise professional judgment by overriding the presumptive risk level per an offender’s score on the Minnesota Sex Offender Screening Tool−3 (MnSOST-3), a sexual recidivism risk-assessment instrument. These overrides enabled us to evaluate whether the use of professional judgment resulted in better predictive performance than did reliance on “actuarial” judgment (MnSOST-3). Using multiple metrics, we also compared the performance of a home-grown instrument (the MnSOST-3) with a global assessment (the revised version of the Static-99 [Static-99R]) in predicting sexual recidivism for 650 sex offenders released from Minnesota prisons in 2012. The results showed that use of professional judgment led to a significant degradation in predictive performance. Likewise, the MnSOST-3 outperformed the Static-99R for both sexual recidivism measures (rearrest and reconviction) across most of the performance metrics we used. These results imply that actuarial tools and home-grown tools are preferred relative to those that include professional judgment and those developed on different populations.
The home-field advantage and the perils of professional judgment: Evaluating the performance of the Static-99R and the MnSOST-3 in predicting sexual recidivism – 2018