Sexual Abuse: A Journal of Research and Treatment [saj] PL103-184 August 1, 2000 9:22 Style ﬁle version Nov. 19th, 1999
Sexual Abuse: A Journal of Research and Treatment, Vol. 12, No. 4, 2000
A Cautionary Note Regarding Nicholaichuk et al.
R. Karl Hanson
and Terry Nicholaichuk
The treatment outcome study by Nicholaichuk, Gordon, Gu, and Wong (2000)
used a novel method for identifying a comparison group of untreated sex offenders
(i.e., drawing from existing criminal history records). A potential problem with
their approach is that older records would be expected to include a dispropor-
tionate numbers of recidivists. Such an artifact is identiﬁed in Nicholaichuk et al.’s
(2000) study; nevertheless, their data continue to suggest a small, positive effect
for treatment even after eliminating the cases in which bias is most likely.
KEY WORDS: sexual offenders; treatment outcome; recidivism research; criminal history records.
The evaluation of treatment programs for sexual offenders is a difﬁcult task.
The crucial treatment objective, reduced sexual recidivism, is not directly ob-
servable during treatment itself. It is often years later that clinicians can tell
whether their interventions have been effective. The rates at which new offenses
are detected is sufﬁciently low (approximately 15% after 5 years; Hanson &
Bussi`ere, 1998) that many years of follow-up are often required (Barbaree,
The recidivismrates of the treatment sample,however, can only be interpreted
in relationship to the recidivism rate of a comparison group of untreated offend-
ers. The optimal comparison group would be identical to the treatment group in
every aspect except exposure to treatment. This ideal of equivalence is most likely
when subjects are selected through some explicitly randomly process. Although
high-quality random assignment studies are possible (e.g., Marques, Day, Nelson,
& West, 1994; Robinson, 1995), they are costly, difﬁcult to administer, and slow
Corrections Research, Department of theSolicitor General of Canada, 340 LaurierAve., West, Ottawa,
Ontario K1A 0P8, Canada; e-mail: firstname.lastname@example.org.
Correctional Service of Canada (Prairies), Suite 601, 230-22nd Street, Saskatoon, Saskatchewan S7K
0E9, Canada; e-mail: nicholaichukTP@csc-scc.gc.ca.
2000 Plenum Publishing Corporation