Are Supervision Violations Filling Prisons? The Role of Probation, Parole, and New Offenses in Driving Mass Incarceration.

Advocates for reform have highlighted violations of probation and parole conditions as a key driver of mass incarceration. As a 2019 Council of State Governments report declared, supervision violations are "filling prisons and burdening budgets." Yet few scholarly accounts estimate the precise role of technical violations in fueling prison populations during the prison boom. Using national surveys of state prison populations from 1979 to 2016, the authors document that most incarcerated persons are behind bars for new sentences. On average, just one in eight people in state prisons on any given day has been locked up for a technical violation of community supervision alone. Thus, strategies to substantially reduce prison populations must look to new criminal offenses and sentence length.