Even Sex Offenders Respond to Incentives

This Slate article by Daniel Engber summarizes how psychologists assess the risks of recidivism by pedophiles.

How do psychologists assess the risk that a sex offender will strike again?

Through a combination of clinical judgment and statistics. A forensic psychologist interviews the convict, speaks with his family, and reviews police reports and prison records. The psychologist combines this research with actuarial assessments designed to predict whether an offender will commit another crime.

I know someone who has spent a great deal of time counseling pedophile sex offenders and assessing their risk of re-offending. My impression is that

1. No matter what the treatment, the recidivisim risk is very high for nearly all pedophile sex offenders, though some offenders do not reoffend.
2. Nearly all pedophile sex offenders deny that they've ever done it before when in fact they have a long list of past victims.
3. Nearly all pedophile sex offenders, even if they have been convicted, say they did it only once and the victim enticed them, when in fact they repeatedly offended against the victim.
4. Pedophile sex offenders are unlikely to re-offend while they are making regular weekly visits to group therapy.
5. Chemical castration works reasonably well for many buy not all pedophile sex offenders.

Overall, the article is a superb summary. The one point in the article that is misleading at best is this:

An offender who admits he has a problem and swears he'll change might be less likely to fall into old patterns than someone who's unapologetic about his crimes.

While this may be correct, there are two problems with the statement:

1. The change in the recidivism rate is small. People who swear they'll change still tend to have a high recidivism rate because
2. It difficult to distinguish the liars from those who really mean it. Even sex offenders respond to incentives. When they figure out that swearing they will change will get them earlier parole or other benefits, they improve their pathological lying skills.