special_k makes some good points.

i guess from the viewpoint of someone who has spent quite a bit of time working IN the prison system, i would like to reiterate that the database is not a tool to predict recidivism.

if you're really interested in this type of thing, i'd suggest you look at how reoffending risks are calculated before someone is released.

Check this for an example - NZ's ROC*ROl. It explains how Risk of Conviction and Risk of Imprisonment are calculated, and situations in which risk calculations are overriden (often in sexual offence cases.

http://www.corrections.govt.nz/public/research/roc/