The Sex Offender Treatment Intervention and Progress Scale (SOTIPS): Psychometric Properties and Incremental Predictive Validity With Static-99R

The Sex Offender Treatment Intervention and Progress Scale (SOTIPS) is a 16-item rating scale designed to assess dynamic risk among adult male sex offenders and degree of change at 6-month intervals during treatment. The purpose of the present study was to examine the psychometric properties of the SOTIPS in a construction sample of 759 adult male sex offenders who were under correctional supervision and enrolled in cognitive-behavioral community treatment in Vermont between 2001 and 2007. The scale showed acceptable interrater reliability. SOTIPS scores at 1, 7, and 13 months after participants began treatment predicted sexual, violent, and any recidivism, and return to prison at fixed 1- and 3-year follow-up periods (AUCs = .60 to .85). Combined SOTIPS and Static-99R scores predicted all recidivism types (AUCs = .67 to .89) and outperformed either instrument alone when both instruments had similar predictive power. Participants who demonstrated treatment progress, as reflected by reductions in SOTIPS scores, showed lower rates of recidivism than those who did not.