The Impacts of Parole Supervision

We study the impacts of a reform to parole supervision in Illinois. The reform reduced the term of supervision for some parolees from 12 months to 6 months. Using a standard difference-in-differences estimator, we find clear evidence that the reform reduced prison re-entry rates. Sharp drops in technical revocation rates drove these reductions. Rates of prison re-admissions linked to new crimes did not change. Cook County court records also show no evidence that the reform increased crime rates among parolees. The reform reduced both the cost of incarceration and the cost of parolee supervision without creating measurable harms to public safety. We develop a conceptual framework that shows how shorter terms of supervision could reduce rates of criminal activity among returning citizens, and we show how the insights of this framework inform on-going debates in many jurisdictions about the policies that govern parole supervision.