Incorporating change information into sexual offender risk assessments using the violence risk scale-sexual offender version.

We examined the use of risk-change information in sexual offender risk assessments featuring the Violence Risk Scale-Sexual Offender version (VRS-SO), a sex offender risk assessment and treatment planning tool. The study featured a combined international sample of 539 sex offenders followed up an average of 15.5 years post-release. Pre- and posttreatment VRS-SO ratings were amalgamated from two treated samples of sex offenders from Canada and New Zealand. Analyses focused on examinations and applications of change data and its relationship to sexual and violent recidivism. VRS-SO change scores were significantly associated with decreases in these outcome criteria with, and without, controlling for indicators of pretreatment risk (e.g., Static-99R score) and individual differences in follow-up time. Applications of logistic regression using fixed 5-year follow-ups generated estimated rates of sexual and violent recidivism at different VRS-SO score thresholds. The use of logistic regression demonstrated a clinically useful and systematic means of combining risk and change information into posttreatment risk appraisals. Implications for the use of change information in the assessment and management of sexual offender risk are discussed.