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Sources of Variability in Estimates of Predictive Validity: A Specification With Level of Service General Risk and Need

NCJ Number
235145
Journal
Criminal Justice and Behavior Volume: 38 Issue: 5 Dated: May 2011 Pages: 413-432
Author(s)
D. A. Andrews; James Bonta; J. Stephen Wormith; Lina Guzzo; Albert Brews; Jill Rettinger; Rob Rowe
Date Published
May 2011
Length
20 pages
Annotation
Level of Service (LS) is one of the most widely used general risk and need assessment tools in criminal justice agencies across North America. However, there is significant interstudy variability in the magnitude of the validity estimates. This study was conducted to examine possible sources of this variability.
Abstract
The predictive validity of LS risk and need increased with length of follow-up period and with investigator allegiance to LS. The combination of these two variables reveals consistent increases in mean predictive validity estimates from modest (in the .20s) through large (in the mid .30s) to very large (in the .40s) in samples of both male and female offenders. The study hypothesized that the "allegiance effect" reflects the integrity of LS implementation and support provided by the agency for risk assessment. This is akin to the difference between "demonstration projects" and "practical" rehabilitation programming in the offender treatment research. Moreover, controls for Canadian versus non-Canadian evaluations reduced the effect of allegiance and length of follow-up to nonsignificant levels. Possible explanations for these findings include the degree of integrity in conducting risk and need assessments, the accuracy of recidivism as the criterion measure, and generalizability across international boundaries. (Published Abstract)