As the size of the “what works” literature has expanded over the last four decades, so have efforts to base correctional policy and practice on the evidence that has accumulated. The embrace of what’s come to be known as “evidence-based practices” is reflected, for example, by growing use of the risk-needs-responsivity model, which prescribes the use of risk and needs assessments so as to prioritize higher-risk offenders for effective interventions that are calibrated to their criminogenic needs, strengths, learning styles, and abilities.
When it comes to sex offenders, to what extent is correctional policy and practice, at least within the U.S., rooted in the evidence? Unfortunately, not much. Since the early 1990s, many states in the U.S. have implemented longer prison sentences for sex crimes, involuntary civil commitment programs, sex offender registration and notification (SORN), residence restrictions, and lifetime probation and parole (Meloy, 2005).
The guiding principle behind these legislative efforts is that the incidence of sexual offending can be reduced by increasing the risk and costs associated with committing a sex offense. While there is very little research that has looked at the impact of longer sentences on sexual offending, the literature has demonstrated that residence restrictions do not reduce sex offense recidivism (Duwe, Donnay, and Tewksbury, 2008). Research on SORN has generally found that it has failed to significantly lower sexual offending (Drake, 2009), although the findings from a few studies suggest there may be conditions under which community notification can be effective (Barnoski, 2005; Duwe and Donnay, 2008). And the one study that’s looked at the impact of a civil commitment program found that it reduced the overall four-year sexual recidivism rate by 12 percent (Duwe, 2014).
Yet, because community notification and civil commitment are costly to operate (Duwe, 2014; Zgoba, Witt, Dalessandro, and Veysey, 2008), it is unclear whether the public safety benefits that may be yielded by these interventions exceed their costs. Moreover, among the 20 states that run civil commitment programs, several have recently been found to be unconstitutional.
So, are there interventions for sex offenders that the evidence shows are effective in reducing sexual recidivism, deliver a positive return on investment (ROI), and are actually constitutional? Currently, there are two interventions—sex offender treatment and Circles of Support and Accountability (CoSA)—that appear to meet these criteria, at least in part.
The most comprehensive meta-analyses have found that sex offender treatment reduces sexual recidivism. In the most recent meta-analysis, Lösel and Schmucker (2015) found that it lowered sexual recidivism by 26 percent and that the best outcomes were associated with programs that delivered cognitive-behavioral and multi-systemic treatment. Cost-benefit analyses have also shown that sex offender treatment delivers a ROI of $2.05 in Washington (Aos and Drake, 2013) and $3.11 in Minnesota (Duwe, 2013a).
The evidence on the effectiveness of CoSA is promising although still tenuous at this point. Research from Canada have shown that it significantly reduces sexual recidivism (Wilson, Cortoni, & McWhinnie, 2009), while a Minnesota evaluation showed that it lowered general reoffending (Duwe, 2013b). Moreover, the Minnesota study found that for every dollar spent on the program, it returned $1.82 in cost avoidance benefits (Duwe, 2013b).
More (and better) evidence is needed, of course, on what works with sex offenders, but there are a few areas where the paucity of research is particularly noteworthy. While the CoSA literature is small but growing, existing research has provided virtually no evidence on whether increases in penalties have contributed to the decline in sexual offending, including sexual recidivism, since the early 1990s. Moreover, in the context of residence restrictions, it is sometimes argued that these laws make it difficult for sex offenders to secure employment and stable housing, which, in turn, exacerbate recidivism outcomes. Unemployment and housing instability may very well increase recidivism risk for sex offenders. To date, however, the literature has not provided the evidence needed to support this view.
Grant Duwe, PhD, is Research Director for the Minnesota Department of Corrections, where he forecasts the state’s prison population, conducts research studies and program evaluations, and develops recidivism risk assessment instruments.
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