Abstract
As substance abuse is common among repeat offenders, treatment is one effective strategy to stop the revolving door of corrections and represents the state's best hope in combating recidivism due to substance abuse. Using probit regression, three treatment eligible groups and their subsequent recidivism rates are examined following one and two year observation periods for offenders who paroled in fiscal year 2005/2006. Relative to non-treated offenders, probobility of recidivism is 18 percent lower among offenders who complete both in-prison and community aftercare treatment; probobility of recidivism is 15 percent lower among offenders who complete in-prison treatment only. This analysis provides quantitative economic evidence that substance abuse treatment programs are effective in reducing recidivism in California.