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Reliability and Validity Study of the Static-99/RRASOR Sex Offender Risk Assessment Instruments

NCJ Number
James Austin Ph.D.; Johnette Peyton M.S.; Kelly Dedel Johnson Ph.D.
Date Published
January 2003
22 pages
Two reliability tests were conducted to ascertain the reliability of three sex offender risk assessment instruments, the Static-99, the Risk Assessment for Sexual Offense Recidivism (RRASOR), and the Minnesota Sex Offender Screening Tool-Revised (MnSOST-R).
Findings indicate that the Static 99/RRASOR is a reliable and valid instrument for assessing sex offenders’ risk to recidivate, and that the level of interrater reliability was unacceptably low for the MnSOST-R because many instrument questions could not be scored from available information. The static-99/RRASOR had higher rates of reliability. The Static-99 was first developed by Canadian researchers and includes 10 items that take into account the offender’s prior criminal history, incidence of violence, relationship to the victim, and personal characteristics that have relevance to the Pennsylvania Board of Probation and Parole (PBPP) parole decision. These variables have been shown to be statistically associated with recidivism in other jurisdictions. Within the Static-99, there are four items that compose a condensed risk assessment instrument known as the RRASOR. The four items comprising the RRASOR largely account for the predictive ability of the Static-99. Significant staff training and item refinement were required to ensure the consistent application of these instruments to Pennsylvania’s sex offender parole population. However, more intensive and effective training is needed to insure consistent scoring across raters. It is also recommended that the age variable be adjusted on the instrument to enhance the already acceptable level of prediction associated with this assessment instrument. The validation sample consisted of 550 cases that reflected prisoners convicted of sex crimes and released either between 1994 and 1995 (N=356), or in 2000 (N=194). 9 tables