For nearly two decades, much of the growth in Michigan’s prison system was caused by a decline in parole grant rates. Thousands of prisoners with good institutional records who had served their minimum sentences were denied release annually.
The size, and thus the cost, of the prison system depend on how many people enter and how long they stay. In a recent study, the Pew Center on the States found that in 2009, Michigan had the longest average time served of any of the 35 states it examined.
Overall, Michigan prisoners served nearly 17 months more than the national norm. For just assaultive offenses, Michigan prisoners served 30 months more than the national average. Each additional month served costs taxpayers $2,100/month. If the 15,009 prisoners Michigan released in 2009 had served the national average, the savings could have exceeded $530 million.
CAPPS worksheet showing approximately $162 million in annual savings from requiring parole after people have served their minimum sentences.