Estimated Cost Savings From Shifting People from Jail or Prison to Probation or Parole
"The calculations in Table 4 assume that for each non-violent offender shifted from prison or jail (at an average cost of about $25,500 to $26,000 per year) to probation or parole (at average cost of $1,300 to $2,800 per year), government corrections systems would save $23,000 to $25,000 per inmate per year. Given the mix of prisoners by offense type (see Table 3), a 50 percent reduction in non-violent-offender inmates would save the federal government about $2.1 billion per year, state governments about $7.6 billion per year, and local governments about $7.2 billion per year, even after factoring in additional probation and parole costs. Across all three levels of government, these savings total $16.9 billion or about 22.8 percent of the total national spending on corrections in 2008."
Schmitt, John; Warner, Kris and Gupta, Sarika, "The High Budgetary Cost of Incarceration," Center for Economic and Policy Research (Washington, DC: June 2010), p. 11.