Shock probation is a legal policy in the United States that allows a judge to order a convicted offender to prison for a short time, and then suspend the remainder of the sentence in favor of probation. The initial experience of prison is hoped to provide an effective deterrent to recidivism. In shock probation, a convicted offender is sentenced to prison and starts serving their sentence. After three to six months, the judge re-sentences the prisoner to probation, and the prisoner is released under supervision. Shock probation is usually considered when a prisoner is a first-time offender and a judge believes, given the circumstances of the case, that the prisoner has a chance at reform which may be enhanced by being released. Shock probation is not used in all U.S. states, and in states where it is used, it is at the discretion of the judge.