ABSTRACT

This study tested 3 decision rules for combining actuarial risk instruments for sex offenders into an overall evaluation of risk. Based on a 9-year follow-up of 940 adult male sex offenders, we found that Rapid Risk Assessment for Sex Offender Recidivism (RRASOR), Static-99R, and Static-2002R predicted sexual, violent, and general recidivism and provided incremental information for the prediction of all 3 outcomes. Consistent with previous findings, the incremental effect of RRASOR was positive for sexual recidivism but negative for violent and general recidivism. Averaging risk ratios was a promising approach to combining these risk scales, showing good calibration between predicted (E) and observed (O) recidivism rates (E/O index = 0.93, 95% CI [0.79, 1.09]) and good discrimination (area under the curve = 0.73, 95% CI [0.69, 0.77]) for sexual recidivism. As expected, choosing the lowest (least risky) risk tool resulted in underestimated sexual recidivism rates (E/O = 0.67, 95% CI [0.57, 0.79]) and choosing the highest (riskiest) resulted in overestimated risk (E/O = 1.37, 95% CI [1.17, 1.60]). For the prediction of violent and general recidivism, the combination rules provided similar or lower discrimination compared with relying solely on the Static-99R or Static-2002R. The current results support an averaging approach and underscore the importance of understanding the constructs assessed by violence risk measures.

The current study used crime scene analysis (CSA) to identify the psychological characteristics of child molesters and examined the contribution of these behavioral themes for sexual offender risk assessment. CSA was conducted on a sample of 424 cases of child sexual abuse in Berlin (Germany) using non-metric Multi-Dimensional Scaling. The analysis revealed the behavioral themes of fixation, regression (sexualization), criminality, and (sexualized) aggression, consistent with previous theories and empirical research in child molestation. The construct validity of the four themes was demonstrated through correlational analyses with known sexual offending measures, ratings of offender motivation, and criminal histories. The themes of fixation and (sexualized) aggression were significant predictors of sexual recidivism and added incrementally to the Static-99 for the prediction of sexual recidivism. The results indicate that crime scene information can inform the assessment of child molesters' risk-relevant propensities and improve the prediction of sexual recidivism.

The current study sought to improve the predictive accuracy of sexual recidivism using the Static-99 risk assessment tool by the addition of detailed crime scene analysis (CSA). CSA was carried out using a Behavioral Thematic Analysis (BTA) approach, the gold-standard in CSA. BTA was conducted on a sample of 167 stranger rape cases using nonmetric multidimensional scaling (MDS). The BTA procedure revealed three behavioral themes of hostility, criminality, and sexual exploitation, consistent with previous research in sexual offending CSA. Logistic regression analysis indicated that the criminality theme was significantly predictive of sexual recidivism and also significantly correlated with previous sexual offense history. Further, the criminality theme led to a significant increase in the incremental validity of the Static-99 actuarial risk assessment instrument for the prediction of sexual recidivism.

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