A Model of Static and Dynamic Sex Offender Risk Assessment

During the last decade, researchers have developed several risk instruments for adult male sex offenders that predict with moderate accuracy their long term risk of sexual reoffending. But because most of these instruments are composed of static, that is unchangeable, risk factors, they are not useful for predicting an individual's short term risk to reoffend or how to reduce or measure changes in that risk. This requires instruments composed of dynamic, that is changeable, risk factors.
The Vermont Department of Corrections (DOC) developed such a dynamic risk assessment instrument in 2001 through a grant from the U. S. Department of Justice. The instrument, the Sex Offender Treatment Needs and Progress Scale (TPS; McGrath & Cumming, 2003), consists of 22 dynamic risk factors linked to sexual offending.
Since 2001, the Vermont DOC's statewide network of community-based sex offender treatment providers have scored every adult male sex offender that they serve on the TPS at intake and every six months thereafter. Providers have used this information for treatment planning, probation and parole officers have used it for case management, and DOC has retained it for research purposes. The DOC now has multiple TPS scores on over 1,100 sex offenders. This data base also contains demographic data on each of these sex offenders and their scores on three other commonly used sex offender risk measures, the Static-99, RRASOR, and VASOR.
Recent research indicates that combining static and dynamic risk factors may better predict sexual offending than either static or dynamic instruments alone. Consequently, this prospective study will examine how the TPS and Static-99, the most commonly used sex offender risk instruments used in the United States, can be combined into an overall model of risk assessment. Analyses will also be conducted to determine if RRASOR and VASOR scores will improve the predictive accuracy of the model.
Recidivism data on approximately 950 adult male sex offenders will be analyzed at three-year fixed follow-up periods for all new charges for sexual, violent, and other offenses. An empirically derived decision matrix will be created to provide guidance to administrators and service providers about how to allocate and deliver services based on an individual's risk to sexually reoffend using a model that integrates offenders' scores on static and dynamic risk measures.

ca/ncf