"For $3,000 per year, a HOPE-style mix of probation, drug testing, sanctions, and treatment only as needed, plus GPS monitoring, could deliver something like 80 percent of the crime-prevention benefits of a prison cell that costs ten times as much. With such a system in place, judges would have a real alternative to incarceration. And so would the governors who are thinking about letting prisoners out to save money. Today, two-thirds of those who leave prison will be back within three years; the exit from a prison is a revolving door. For felony probationers, the incarceration rate within three years is about 50 percent. If the "outpatient prison" could do for recidivism among parolees what HOPE did for new crimes by probationers, five years from now we could have many fewer people in prison than we do today, and half as much crime."