Forty percent of the total and 77 percent of the psychopaths (as defined by the Psychopathy Checklist) committed a violent offense. It was possible to predict outcome with considerable accuracy using combinations of childhood history, adult history, index offense, and institutional or program variables. However, the Psychopathy Checklist alone performed at least as well as any combination of variable and also improved upon the prediction based on criminal history variables. Psychopaths continued to recidivate at a higher rate than nonpsychopaths even beyond age 40. (Author abstract)