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 while many similar parolees continued to receive 12 months of supervision. We evaluate the impact of the reform using a standard difference-in-differences estimator, and we find clear evidence that the reform reduced prison re-entry rates. Sharp drops in rates of technical revocations drove these reductions. Rates of prison re-admissions linked to new crimes did not change. We merge data from Cook County Courts with our data on state prison admissions and releases, and we find 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 harms to public safety.