Treatment of Sex Offenders

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justified on the grounds that they provide incremental information (Babchishin
et al., 2012b ; Welsh, Schmidt, McKinnon, Chattha, & Meyers, 2008 ). For some
scales the developers propose starting with a commonly used risk scale and adjusting
the overall rating based on the scores of an incrementally valid, additional risk
instrument (e.g., Helmus, Hanson, Babchishin, & Thornton, 2014 ). Also, recent
research indicates that averaging the risk ratios of different risk tools is a promising
approach to obtaining a better overall evaluation of relative risk (Lehmann, Hanson
et al. 2013 ), as opposed to other approaches, such as taking the highest or lowest
risk estimate. Hence, a strength of actuarial risk assessment is the inclusion of a
range of empirically validated risk factors or scales, which under certain circumstances
(see Lehmann, Hanson et al. 2013 ) could be combined into an overall risk
judgment of recidivism risk with better predictive accuracy than a single scale.
Selected Examples of Actuarial Risk Scales for Sex Offenders
Below, specific examples of risk scales for sex offenders will be discussed. Note
that they are not meant as an exhaustive list of scales available—they are illustrative
examples of scales we are most familiar with. This chapter was not intended to
provide a detailed review of actuarial risk scales available.
The Static-99/R
The most commonly used static sex offender risk assessment tools in Canada and
the United States are the Static-99 and Static-99R (Hanson & Thornton, 2000 ;
Helmus, Thornton, Hanson, & Babchishin, 2012 ; Interstate Commission for Adult
Offender Supervision, 2007 ; Jackson & Hess, 2007 ; McGrath, Cumming, Burchard,
Zeoli, & Ellerby, 2010 ; Neal & Grisso, 2014 ). The Static-99/R is 10-item actuarial
scales designed to assess sexual recidivism risk of adult male sex offenders. The
items and scoring rules for Static-99 (Hanson & Thornton, 2000 ) and Static-99R
(Helmus, Thornton et al., 2012 ) are identical with the exception of updated age
weights for the Static-99R. The scale developers have recommended that Static-
99R be used in place of the original scale (Helmus, Thornton et al., 2012 ). Static- -
99/R contains items covering the broad constructs of age and relationship status
(i.e., whether the offender has ever lived with a lover for two or more years), sexual
deviance (e.g., stranger victims, noncontact sexual offences, prior sex offenses), and
general criminality (e.g., number of prior sentencing occasions, index nonsexual
violence, prior nonsexual violence) identified in meta-analytic research (Hanson &
Bussière, 1998 ; Hanson & Morton-Bourgon, 2005 ).
Accordingly, the strength of the risk tool is that it only uses risk factors empirically
associated with sexual recidivism. Also, explicit rules for combining the factors
into a total risk score are provided (A. Harris, Phenix, Hanson, & Thornton, 2003 ).