A Quasi-Experimental Evaluation of High-Intensity Inpatient Sex Offender Treatment in the Netherlands

Abstract

The current study quasi-experimentally assessed the outcome of high-intensity inpatient sex offender treatment in the Netherlands in terms of sexual and violent (including sexual) recidivism. It was hypothesized that treated sex offenders would show lower recidivism rates than untreated sex offenders of the same risk level. In line with the risk principle of the Risk, Need, Responsivity (RNR) model, we predicted that this would especially hold true for offenders of higher risk levels. The study sample consisted of 25% of all convicted Dutch sex offenders not referred to any form of treatment and discharged from prison between 1996 and 2002, and all convicted Dutch sex offenders referred to inpatient treatment who were discharged between 1996 and 2002. Static-99R risk levels of these 266 offenders were retrospectively assessed and survival curves regarding sexual and violent (including sexual) recidivism were compared between treated and untreated offenders, controlling for level of risk. Mean follow-up was 148.0 months (SD = 29.6) and the base rate of sexual recidivism was 15.0% and 38.4% for violent (including sexual) recidivism. Cox regression survival analyses showed marginally significant lower failure rates regarding sexual recidivism for treated high-risk offenders only, and significantly lower failure rates regarding violent (including sexual recidivism) for treated sex offenders of moderate-high and high-risk levels. No treatment effects for low and low-moderate risk offenders were found. Results underscore the risk principle of the RNR model: Treatment is more effective when its dosage is attuned to risk level.

On the Effectiveness of Sexual Offender Treatment in Prisons: A Comparison of Two Different Evaluation Designs in Routine Practice

“…In both analyses, there were no significant effects of treatment in prison on the rate of sexual reoffending. This is in accordance with recent meta-analyses (Schmucker & Lösel, 2015, 2017) and several quasi-experimental primary studies (Abracen, Looman, Ferguson, Harkins, & Mailloux, 2011; Grady et al, 2017; Olver et al, 2012; Smallbone & McHugh, 2010; Smid, Kamphuis, Wever, & van Beek, 2016). Some of the latter studies had smaller samples and applied matching methods that may have impaired equivalence of TG and CG.…”

“…Our consistently positive, although only partially significant, finding on nonsexual recidivism criteria in both of our analyses seems to be a robust and encouraging finding. It agrees with studies that used only one matching method (Grady et al, 2017; Olver et al, 2012; Smid et al, 2016). It is also supported by meta-analyses (Schmucker & Lösel, 2015, 2017).…”

Evidence comes by replication, but needs differentiation: the reproducibility issue in science and its relevance for criminology

“…As mentioned above, custodial programs had no significant effect on the rate of sexual recidivism, but various studies suggest that there may be an impact on other outcomes, such as a lower rate of nonsexual reoffending, or more delayed or less harmful sexual reoffending (e.g., Olver et al 2012;Smid et al 2016). Evaluations of sexual offender treatment often raise more questions than answers (Grady et al 2015).…”

Risk Levels, Treatment Duration, and Drop Out in a Clinically Composed Outpatient Sex Offender Treatment Group

“…Should such a group be available in the future, this question certainly needs to be addressed first and foremost. However, although it is theoretically possible that the clinical treatment selection in this sample has lead to better treatment results than a risk-oriented selection would have, this is very unlikely given the accumulating evidence underlining the importance of the risk principle both in correctional treatment in general (Bonta et al, 2000;Lowenkamp & Latessa, 2002) and in the treatment of sex offenders specifically Olver, Nicholaichuk, Gu, & Wong, 2013;Smid, Kamphuis, Wever, & Van Beek, 2014).…”