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Recently, Wollert and colleagues proposed that sex offender recidivism estimates should be stratified by age and they developed an age-stratified scale called the MATS-1 (Multisample Age-Stratified Table of Sexual Recidivism). The purpose of this article is to highlight concerns with the development of the MATS-1 and to validate the scale using 3,510 sex offenders from 14 unique samples. Concerns with the scale's development fall into three categories: approximations leading to considerable loss of precision, absence of appropriate statistical tests, and the use of inappropriate statistical techniques. The predictive accuracy of the MATS-1 (Area Under the Curve [AUC] = .663) was significantly lower than Static-99R (AUC = .708). The MATS-1 also significantly underestimated recidivism for some offenders. Both the relative and absolute predictive properties of the MATS-1 were not stable across samples. We conclude that the MATS-1 is not appropriate to use for applied risk assessment. Proposals are made for alternate ways to develop risk scales using the age-stratification method.

Given the widespread use of empirical actuarial risk tools in corrections and forensic mental health, it is important that evaluators and decision makers understand how scores relate to recidivism risk. In the current study, we found strong evidence for a relative risk interpretation of Static-99R scores using 8 samples from Canada, United Kingdom, and Western Europe ( N = 4,037 sex offenders). Each increase in Static-99R score was associated with a stable and consistent increase in relative risk (as measured by an odds ratio or hazard ratio of approximately 1.4). Hazard ratios from Cox regression were used to calculate risk ratios that can be reported for Static-99R. We recommend that evaluators consider risk ratios as a useful, nonarbitrary metric for quantifying and communicating risk information. To avoid misinterpretation, however, risk ratios should be presented with recidivism base rates.

Actuarial risk assessment scales and their associated recidivism estimates are generally developed on samples of offenders whose average age is well below 50 years. Criminal behavior of all types declines with age; consequently, actuarial scales tend to overestimate recidivism for older offenders. The current study aimed to develop a revised scoring system for two risk assessment tools (Static-99 and Static-2002) that would more accurately describe older offenders' risk of recidivism. Using data from 8,390 sex offenders derived from 24 separate samples, age was found to add incremental predictive validity to both Static-99 and Static-2002. After creating new age weights, the resulting instruments (Static-99R and Static-2002R) had only slightly higher relative predictive accuracy. The absolute recidivism estimates, however, provided a substantially better fit for older offenders than the recidivism estimates from the original scales. We encourage evaluators to adopt the revised scales with the new age weights.

Empirical actuarial risk tools are routinely used to assess the recidivism risk of adult sexual offenders. Compared with other forms of risk assessment, one advantage of actuarial risk tools is that they provide recidivism rate estimates. Previous research, however, suggests that there is considerable variability in the recidivism rates associated with the most commonly used sexual offender risk assessment tools (Static-99/R, Static-2002/R). The current study examined the extent to which the variability in the recidivism rates across 21 Static-99R studies ( N = 8,805) corresponded to the normative groups proposed by the STATIC development group (routine, treatment, high risk/high need). We found strong evidence that routine (i.e., complete) samples were, on average, less likely to reoffend with a sexual offense than offenders in the high-risk/high-need samples (i.e., those explicitly preselected on risk-relevant variables external to STATIC scales). The differences between routine/complete and high-risk/high-need samples, however, were only consistently observed for offenders with low or moderate scores; for offenders with high STATIC scores, the 5-year sexual recidivism rates for these two groups were not meaningfully different. There was only limited evidence to support treatment samples as a distinct sample type; consequently, the use of separate normative tables for treatment samples is not recommended. The current results reinforce the value of regularly updating the norms for empirical actuarial risk tools. Options are discussed on how STATIC scores could be used to inform recidivism rates estimates in applied assessments.

The Static-99 is an instrument commonly used to measure the likelihood of recidivism among sex offenders. The current study explores whether the Static-99 is an effective predictor of relapse among Catholic clergy who have had sexual contact with minors. Static-99 scores were compiled for 337 treated clergy who had offended against minors, including 21 who were known to have relapsed after treatment. Clergy were followed up for 5 to 25 years posttreatment ( M = 16.05; SD = 5.12) after their completion of treatment. Post release, they were closely supervised, with explicit rules limiting their contacts with minors and church officials monitoring their compliance with posttreatment plans. Descriptive information on the victims of clergy sex offenders is provided. Although all clergy offenders had the same score on 4 of the 10 Static-99 items, Static-99 total scores still significantly predicted relapse with a moderate to large effect size (area under the curve [AUC] = .672; Cohen's d = .808). Predictive accuracy of each item is also reported. Issues concerning the use of the Static-99 with this population are discussed.