Outcomes in a Community Sex Offender Treatment Program: A Comparison Between Polygraphed and Matched Non-polygraphed Offenders

Abstract

This study compared a group of 104 adult male sex offenders who received community cognitive-behavioral treatment, correctional supervision, and periodic polygraph compliance exams with a matched group of 104 sex offenders who received the same type of treatment and supervision services but no polygraph exams. Polygraph exams focused on whether participants were following their conditions of community supervision and treatment and had avoided committing new sexual offenses. The two groups were exact pair-wise matched on three variables: (1) Static-99 risk score (Hanson & Thornton 2000, Law and Human Behavior, 24, 119-136), (2) status as a completer of prison sex offender treatment, and (3) date placed in the community. At fixed 5-year follow-up periods, the number of individuals in the polygraph group charged with committing a new non-sexual violent offense was significantly lower than in the no polygraph group (2.9% versus 11.5%). However, there were no significant between-group differences for the number of individuals charged for new sexual (5.8% versus 6.7%), any sexual or violent (8.7% versus 16.3%), or any criminal offense (39.4% versus 34.6%). The results are discussed in terms of their clinical and research implications.

The case for polygraph testing of sex offenders

“…The study, however, was unable to examine the relationship between this and any reduction in future reconviction rates. McGrath, Cumming, Hoke, and Bonn-Miller (2007), in a well designed evaluation, compared 104 sex offenders in Vermont who received treatment in programmes involving PCSOT with 104 matched offenders in programmes where polygraphy was not used. At 5 year follow-up they found no difference in sex offence recidivism rates, but they did find a significantly lower rate of reconviction for non-sexual violent offences.…”

Interview or Interrogation: A Critical Review of the Efficacy and Ethicality of Post-Conviction Sex Offender Polygraph Testing

“…Lastly, the only real study that spoke towards the ability of the polygraph to curb recidivistic behavior in sex offenders (McGrath, Cumming, Hoke, & Bonn-Miller, 2007), the whole purpose behind sex offender rehabilitation, reported fairly underwhelming results. Because of the fact that periodic polygraph testing only reduced violent, nonsexual recidivism amongst sex offenders not only speaks little to its ability to curb recidivism in general, but also questions its need to be specifically applied in sex offender rehabilitation.…”

“…The only article from the past decade that could be found for this review was a study analyzing the re-offense rates of polygraphed sex offenders versus those of nonpolygraphed offenders (McGrath, Cumming, Hoke, & Bonn-Miller, 2007). Researchers cited the statements made by proponents of the polygraph concerning the polygraph's ability to not only elicit more honest answers to questions concerning high-risk behavior, but also to act as a deterrent to sex offender recidivism.…”

“…When examining the empirical literature, the most obvious weakness in the design of the experiment is the generally paltry sample sizes. Aside from three of the studies examined in this review Grubin, & Madsen, 2006;McGrath, Cumming, Hoke, & Bonn-Miller, 2007), all of the studies focused were conducted with sample sizes well under 100 participants, one of which utilized as few as 14 subjects (Wilcox, & Sosnowski, 2005). These relatively small sample sizes, coupled with the high dropout rate of many of the studies, can not only call into question the value and validity of the results from these studies, but also severely limit their generalizability.…”

“…However, possibly the most glaring gap in the literature as it stands is deficiency on experimental and research studies monitoring the effect of post-conviction polygraph testing on rates of recidivism amongst sex offenders. Amongst contemporary literature on the subject of post-conviction polygraph testing, only one article was found that sought to monitor this connection (McGrath, Cumming, Hoke, & Bonn-Miller, 2007). While the article was fairly thorough, a single study is hardly enough to confirm the effect of (as can be seen from the literature) an incredibly controversial treatment method.…”