The study findings show positive outcomes for Kentucky corrections-based substance abuse treatment, and findings also show the importance of a systematic data-collection approach in evaluating correctional treatment programs. Regarding outcomes for the prison/jail substance abuse treatment programs, participants who reported any substance use following release from custody were significantly lower at follow-up (43.9 percent) compared to baseline (94.1 percent). In addition there were few differences in substance use at follow-up between offenders who participated in community aftercare compared to those who did not; however, those offenders who participated in aftercare treatment had reduced rates of recidivism within 1 year postrelease. The innovative systematic data-collection approach involves corrections counselors using personal digital assistants (PDAs) to collect and enter clinical assessment data for the baseline period (time of in-prison treatment entry). Follow-up interviews 12 months postrelease were conducted by a university research team with a stratified random sample of 700 offenders. All had enrolled in treatment during the final 6-9 months of their sentence. They had participated in 6 prison and 18 jail programs between April 2005 and June 2007. Follow-up data were obtained through 30-minute phone interviews. 1 figure and 23 references