A Static-99R Validation Study on Individuals With Mental Disorders: 5 to 20 Years of Fixed Follow-Up After Sexual Offenses

Abstract

‘The Static-99R is one of the most commonly used risk assessment instruments for individuals convicted of sexual offenses. It has been validated for use on many populations, but few studies specifically target and describe individuals with mental disorders. Additionally, research on the discriminative properties (how well the instrument separates recidivists from non-recidivists) of the instrument over longer follow-up periods is scarce. This article evaluated the validity of the Static-99R using a cohort of individuals with mental disorders convicted of sexual offenses in Sweden (N = 146) with fixed 5-year (n = 100), 10-year (n = 91), 15-year (n = 79), and 20-year (n = 36) follow-up periods. A Static-99R cut score of 6 demonstrated the highest Youden index, maximizing sensitivity (72.7%) and specificity (74.2%), with 25.8% of recidivists correctly assumed to reoffend sexually and 95.7% of non-recidivists correctly assumed not to. The Static-99R instrument demonstrated adequate discrimination (AUC = 0.79, CI 95% = 0.70–0.87, and OR = 1.45, CI 95% = 1.14–1.84, p < 0.001, 5-year fixed follow-up), with only marginal differences for 10-, 15-, and 20-year fixed follow-up (AUC = 0.73, 0.74, and 0.74 and OR = 1.31, 1.36, and 1.40, respectively). Calibration (quantifying risk and correspondence with the instrument’s norms) was acceptable (Brier = 0.088, P/E = 0.70, E/O = 1.43), with the routine sample norms displaying a decisively better fit to the study cohort compared to the high-risk/high-need sample norms. The results affirm the recommendation that, when in doubt and where there is no recent local norm group large enough available, the Static-99R routine sample found in the evaluators’ workbook should be used.

Static-99R: Strengths, limitations, predictive accuracy meta-analysis, and legal admissibility review.

“…Only six U.S. cases challenged the use of Static-99/R in individuals who, by some characteristic (e.g., young age at index offense, cognitive disability, or mental health diagnosis) were atypical of the samples used to develop and validate Static-99R. Although atypical and less commonly researched, the scales have been valdated for use with developmentally delayed (Hanson, Sheahan, & VanZuylen, 2013) and mentally disordered individuals (Baudin et al, 2021; Hanson et al, 2007). Less is known about validity for individuals with specific types of neurocognitive abnormalities such as brain damage or dementia, although there is no a priori reason to believe Static-99R would function differently with those groups.…”

Predictive and incremental validity of the Static-99, Static-99R, and STABLE-2007 for sexual recidivism: A diagnostic test accuracy network meta-analysis (DTA-NMA).

“…More specifically, out of a total of 689 publications identified via literature search and gleaned from previous meta-analyses, 211 publications met our eligibility criteria, from which we excluded 157 publications due to missing information on per-risk-level sexual recidivism rates. Except for the more recent studies, most of the studies had been included in prior meta-analyses (Baudin et al, 2021; Leguízamo et al, 2017; Looman et al, 2021; Toma et al, 2022; Wong, 2021). In cases where samples had been reported in more than one publication, only the information provided in the most recently published article was included in the analysis.…”

“…The earliest study, which evaluated 142 adult males from Switzerland across a 5-year follow-up period, reported the optimal cutoffs corresponding to a raw score of 4 for both the Static-99 (moderate-high [III]) and Static-99R (above average [IVa]; Gonçalves et al, 2020). In a second study, based on 146 male individuals from Sweden across 5-and 20-year follow-up periods, a slightly higher cutoff at the raw score of 6 for the Static-99R (well above average [IVb]) was observed; however, the difference from the raw score of 4 (above average [IVa]) was described as negligible (Baudin et al, 2021). The third study (Chang et al, 2023), based on 860 and 359 adult males across 5-and 10-year follow-up periods (Phenix, Fernandez, et al, 2016), noted the optimal cutoff at the raw score of 5 for the Static-99R (above average [IVa]).…”

Reliability and validity of the Static-99R in sex offenders with intellectual disabilities

“…It has considerable research support, with meta-analyses showing moderate predictive accuracy with AUCs around 0.70 (Hanson and Morton-Bourgon, 2009;Singh et al, 2011;Helmus et al, 2012a;Helmus et al, 2021). Although offenders with low intellectual functioning/ID are sometimes included in the total sample, sample sizes are usually too small to infer strong statements (Harris et al, 2003;Hanson et al, 2015;Baudin et al, 2021). The Static-99R consists of 10 static items relating to demographic, offence and victim information.…”