Despite all the attention paid to the growing prison populations in the United States since the early 1990s, it remains, as it has throughout recent history, that probation accounts for the largest portion of those under the custody of the criminal justice system. The U.S. Department of Justice estimates that at the end of 2015, there were more than 3.7 million adults under the supervision of U.S. probation authorities, compared to 1.5 million in prison, 870,000 on parole, and 728,000 in local jails. And while probation is not often thought about within the context of “mass incarceration” in the United States, probation directly impacts prison and jail populations in two specific ways. First, a sentence of probation for a felony offense is the most frequent alternative to a prison sentence. Second, the revocation of probation can directly lead to the imposition of a sentence to prison or jail, depending on the nature of the original conviction offense. During 2015, in the United States, it is estimated that 12% of all probationers exiting supervision were incarcerated due to probation revocation, which translates to an estimate of more than 233,000 probationers annually.
Probation revocation means that the sentencing court has determined that a violation of the conditions of probation have occurred, and because of this, the original probation sentence is no longer appropriate. As a result of a probation sentence being revoked, the sentencing court imposes a different (usually more serious) sanction on the offender. Often, those on probation for a felony offense who have their probation revoked are sentenced to prison, leading to their admission to prison. Indeed, given this link, scholars and practitioners have identified reducing probation revocation as one strategy to reducing prison populations, and jurisdictions often focus on reducing probation revocations as a means to lowering their commitments to prison. Probation revocation can result from either new arrests or violations of technical aspects of the sentence, such as missed appointments or non-compliance with treatment orders. However, whether or not a probation sentence is revoked as a result of these violations varies from jurisdiction to jurisdiction. This variation in the use of probation revocation as a response to violations of probation illustrates the localized nature of revocation proceedings, and attempts to reduce these disparities have taken many forms. These efforts to reduce the impact of probation revocations on prison admissions have ranged from providing local jurisdictions with financial incentives to respond to revocation-eligible violations with sanctions other than incarceration, to legislative efforts to prohibit sentences to prison as a response to probation revocations stemming from technical violations or instances where public safety is not threatened.