An important limitation of the study flows from this
data having been collected retrospectively, with every-
one involved knowing, a priori,the recidivism/nonre-
cidivism status of the offender. In addition, the same
sample was used both to develop the instrument and to
test it. The potential for retrospective recall bias, the
retrospective nature of the study, and the lack of cross-
validation called urgently for a truly prospective study
of dynamic risk factors in sexual offenders.
Karl Hanson and Andrew Harris responded to these
shortcomings, splitting the SONAR into two parts, man-
ualizing the assessment, and expanding on the first 5
items of the SONAR to form the STABLE–2000 and the
final 4 items of the SONAR to form the ACUTE–2000.
The STABLE–2000 and ACUTE–2000 were subse-
quently tested in a truly prospective study using more
than 1,000 sexual offenders on community supervision.
Both tests showed predictive ability above that available
to static assessment alone. That study led to the devel-
opment of two new tests with even better predictive
validity: the STABLE–2007 and the ACUTE–2007.
These two measures have demonstrated predictive
validity beyond that available to static assessment alone
and beyond that of the SONAR and the STA-
BLE–2000/ACUTE–2000 packages. The authors do not
support or recommend the use of the SONAR but rec-
ommend the STABLE–2007 and ACUTE–2007, both
available from the authors, for assessing dynamic
changes in risk in sexual offenders.Andrew J. R. HarrisSee alsoMinnesota Sex Offender Screening
Tool–Revised (MnSOST–R); Rapid Risk Assessment
for Sexual Offense Recidivism (RRASOR);
Risk Assessment Approaches; Sex Offender Risk
Appraisal Guide (SORAG); STATIC–99 and
STATIC–2002 Instruments; Violence Risk
Appraisal Guide (VRAG)Further Readings
Hanson, R. K., & Harris, A. J. R. (2001). A structured
approach to evaluating change among sexual offenders.
Sexual Abuse: A Journal of Research and Treatment,
13 (2), 105–122.
Hanson, R. K., Harris, A. J. R., Scott, T.-L., & Helmus, L.
(2007). Assessing the risk of sexual offenders on
community supervision: The Dynamic Supervision Project
(User report, Corrections research). Ottawa, ON, Canada:
Public Safety Canada. Retrieved from http://www.
ps-sp.gc.ca/res/cor/sum/cprs200709-en.aspSEXOFFENDERRECIDIVISM
Sex offender recidivism refers to the commission of a
subsequent offense by a sex offender on release. The
base rates of sexual offending have been found to range
anywhere from 4% to 71% across studies. Some
research findings suggest that the risk of re-offending
may differ according to the sex offender typology.
Furthermore, there is some research that suggests that
there are various static and dynamic risk variables that
can increase the likelihood of re-offense. However, there
has been a considerable amount of debate in the litera-
ture about how sex offender recidivism should be oper-
ationalized. These debates center on the definition of a
subsequent re-offense, how to handle unreported
crimes, and the duration of the follow-up period.Sex Offender Recidivism
Although there have been numerous individual studies
assessing recidivism rates of sex offenders, Hanson
and his colleagues have conducted two seminal meta-
analyses examining recidivism rates of sex offenders.
In studying sex offender recidivism, meta-analyses
are superior to individual studies as they can statisti-
cally combine results from several studies, thus
increasing the generalizability of the findings.
Hanson and Bussière conducted a meta-analysis of
61 recidivism studies, which provided information on
28,972 sexual offenders. They found that, on average,
the sexual recidivism rate was 13.4% after between 4
and 5 years. When they examined sexual recidivism by
the type of sex offender, they found a recidivism rate of
18.9% for rapists and 12.7% for child molesters. When
they examined recidivism rates for nonsexual violent
recidivism, they found an overall recidivism rate of
12.2%, with child molesters re-offending at a rate of
9.9% and rapists at 22.1%. Finally, when they defined
re-offending as any re-offense (sexual, violent nonsex-
ual, or nonviolent nonsexual), Hanson and Bussière
found an overall recidivism rate of 36.3%, with 36.9%
for child molesters and 46.2% for rapists.
In 2005, Hanson and Bourgnon conducted another
meta-analysis of 82 recidivism studies providing infor-
mation on 29,450 sex offenders over an average of 5 to
6 years postrelease. This time they found an average
sexual offense rate of 13.7%, a violent nonsexual re-
offense rate of 14.3%, and a general (including sexual,
violent nonsexual, or nonviolent nonsexual) re-offense
rate of 36.2%.726 ———Sex Offender RecidivismS-Cutler (Encyc)-45463.qxd 11/18/2007 12:44 PM Page 726