Conventional wisdom says people released after serving time for sex crimes are likely to strike again. The numbers aren't as certain.
Among convicted criminals released from prison, sex offenders released from prison are less likely to be arrested for any new crime than most other offenders, with the notable exception of murderers, researchers say. Child molesters' rate of recidivism is at least as low as the group of sex offenders taken as a whole. Abusers of children within their own family have a lower rate still.
"The observed rate of sexual offenders' recidivism is much lower than commonly believed," says R. Karl Hanson, senior research officer at Public Safety Canada, who has studied the issue for decades. When he speaks to groups, including police officers or therapists, and asks them to estimate the observed rate of sex-crime re-offense, he typically hears numbers such as 70% to 90%. But his review of available research in Canada and the U.S. finds the typical rate is 25% to 30% over 20 years.
One reason for the numerical confusion may be that supporters of sex-offender registries who say sex offenders are more likely than not to re-offend are considering the rate of repeat sex offenses of sex criminals compared with the rate of sex offenses of prisoners released for other crimes. Sex criminals are less likely to be arrested for another crime of any type, but they commit more sex crimes than other groups of criminals. (In general, criminals are more likely to commit crimes in their category than are criminals from other categories.)
All these numbers need to be approached with some skepticism. There also are time limitations to many of the studies, which typically stop tracking the rate of repeat offenses after just three to five years. Pooling all sex crimes together also muddles the picture, as different types of criminals -- say, rapists, child molesters, exhibitionists -- show very different behavior after release from prison. And looming over all of this is the unknown of what proportion of sex crimes go unreported -- particularly within families, a major source of child sexual abuse.
Tracking outcomes for years after release is expensive and slow to show results. The Bureau of Justice Statistics has the most thorough recent U.S. study, covering more than 9,000 male sex offenders released in 15 states in 1994. The study found that sex criminals were less likely to be reconvicted over the following three years than the group of all released prisoners -- 24% compared with 47%. Child molesters had a lower rate, of 20.4%.
The study hasn't been updated, says co-author Matthew Durose, a statistician with the bureau, because "given the time required to collect criminal history information from offenders, it's not something that can be done on a more regular basis." As a result, there are little data measuring the effect of the past decade's spate of state measures, such as sex-offender registries and laws keeping convicted sex offenders a certain distance from schools.Also, a short period of follow-up -- such as the three years of the U.S. government study -- is especially susceptible to unreported crimes, Dr. Hanson says.
Counting crimes that go unreported is, of course, paradoxical. One approach is to extrapolate a true crime rate from victimization surveys and compare that with reported crime, typically finding that roughly 90% of sex crimes go unreported. Some put the estimate even higher.