Utilization and Implications of the Static-99 in Practice

The Static-99 is the most commonly used risk assessment instrument for sexual
violence in North America and its results can affect highly consequential decisions made in the criminal and civil justice systems. Despite its influence, few studies have systematically examined how the Static-99 is used by clinicians in practice. The current study compares the Static-99 ratings of clinicians to those of researchers for 100 adult males who completed an outpatient sex offender treatment program and were followed up over an average of about 4 years. Results showed good agreement between the ratings of clinicians and researchers for total scores on the Static-99, as well as for most individual items. Ratings by clinicians tended to be slightly lower than those made by researchers. The predictive validity of ratings made by clinicians and researchers was very similar and moderate in terms of effect size. In 30 cases, clinicians used discretion to “override” or adjust the Static-99 ratings when making final risk judgments, but the predictive validity of the clinical adjusted ratings was worse than that of the original Static-99 ratings made by clinicians. The need for quality assurance and training are discussed along with the need for clear empirically supported guidelines regarding overrides.