Updating Probability in Sex Offender Risk Assessment

Elwood, Richard W.

doi:10.1177/0306624x17711880

Cited by 4 publications

(1 citation statement)

References 60 publications

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“…A second line of empirical inquiry, known as the constant multiplier, purports to produce lifetime sexual recidivism rates (Doren, 2010; Elwood, 2018). This is accomplished by dividing long‐term observed base rates of sexual recidivism (e.g., 20‐year values) by short‐term base rates (e.g., 5‐year values).…”

Section: Introductionmentioning

confidence: 99%

Illuminating the dark figure of sexual recidivism

Abbott

2020

Behavioral Sci & The Law

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Detected or reported ("observed") rates of sexual reoffending have long been recognized as underestimating the occurrence of actual sexual recidivism. Past attempts to bridge the gap between the two rates have been unsuccessful. Scurich and John try to reverse this course by presenting a simulation model to estimate the predicted actual sexual recidivism rates among individuals convicted of sexual offenses based on three parameters; they also apply these data to calibrate the sexual recidivism rates from four sexual recidivism studies. The accuracy of the predicted actual sexual recidivism rates is wholly dependent upon the reliability of the inputs to the model. This analysis relies upon scientific studies and literature to delve into the precision of the parameters of Scurich and John in relation to the accuracy of their predicted actual sexual recidivism rates and the validity of the calibration process. The results reveal that some of the assumptions by Scurich and John about the parameters are supported empirically, while others are not. Overall, the simulation model parameters suffer from significant deficiencies that likely produce inaccurate predicted actual sexual recidivism rates. Moreover, the methodologies of the comparison studies used in the calibration process do not actually meet the requirements of the analytic strategy of Scurich and John, which effectively invalidates their findings. Until computational strategies are employed that account for linear and nonlinear effects of model parameters, closing the gap between observed and actual sexual recidivism rates will remain elusive.

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Section: Introductionmentioning

confidence: 99%

Illuminating the dark figure of sexual recidivism

Abbott

2020

Behavioral Sci & The Law

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Psychometric Issues in SVP Risk Assessment

Elwood¹,

Kolbeck²

2019

Sexually Violent Predators: A Clinical Science Handbook

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

et al. 2021

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‘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.

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Updating Probability in Sex Offender Risk Assessment

Cited by 4 publications

References 60 publications

Illuminating the dark figure of sexual recidivism

Illuminating the dark figure of sexual recidivism

Psychometric Issues in SVP Risk Assessment

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

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