A new report by The Sentencing Project describes the changes in policy and practice that have enabled five states to reduce their prison populations between 14-25% over the past decade. Decarceration Strategies: How 5 States Achieved Substantial Prison Population Reductions shows how these states have achieved far more significant decarceration than the national average. 

The five states profiled in the report were selected for their geographic and political diversity, and can serve as decarceration roadmaps for other states. Each has implemented a range of reforms in policy as well as decisionmaking by practitioners. These included:

• Connecticut: Declined 25%, 2007-2016
  Focused on reducing young people’s contact with the justice system through reducing school suspensions, changing criteria for detention, and raising the age of adult jurisdiction from 16 to 18.
   
• Michigan: Declined 20%, 2006-2016
  Increased parole grants by expanding capacity of the parole board, and reduced returns to prison by establishing Technical Rule Violator centers for enhanced programming and services.
   
• Mississippi: Declined 17.5%, 2008-2016
  Reduced time served in prison by scaling back the “truth in sentencing” policy from 85% time served to 25%, and applied changes retroactively; adopted a risk assessment instrument that contributed to doubling of parole approval rate.\
   
• Rhode Island: Declined 23%, 2008-2016
  Reduced time served in prison by establishing earned-time credits of 10 days per month, and eliminated mandatory sentences for drug crimes.
   
• South Carolina: Declined 14%, 2008-2016
  Reduced parole violator revocations to prison through diversion to alternative sanctions and reduced returns of 17-25 year-olds through enhanced job-related prison programming and Intensive Aftercare reentry services.