Implications of Static-99 Field Reliability Findings for Score Use and Reporting

Abstract

The Static-99 is a well-researched measure used in many courtroom and correctional settings to help make decisions about sexual offenders. But, as with most forensic assessment measures, we know much more about interrater agreement for the Static-99 in formal research studies than in routine forensic and correctional practice. This study describes “field reliability” for the Static-99 in two states that use the Static-99 for routine correctional procedures, Texas ( N = 600) and New Jersey ( N = 135). Rater agreement coefficients were strong for Static-99 total scores (intraclass correlations = .79 and .88), but the total scores assigned by pairs of evaluators differed for approximately 45% of offenders in each state. Because each individual Static-99 score has a unique interpretation, and a 1-point difference in a Static-99 score can have substantial practical implications for decision making, these findings suggest the need for administration procedures or interpretation methods that acknowledge and account for measurement error in Static-99 total scores.