The total U.S. prison population declined by 2.4% since 2009. Five of the states with rising prison populations have experienced double-digit increases, led by Arkansas, with a 17% rise since 2008. While sharing in the national crime drop, these states have resisted the trend toward decarceration. And of those states with declining prison populations, 16 have had less than a 5% decline since their peak years. The decline in the federal prison population has been of this magnitude: 1% since 2011.
Just as mass incarceration has developed primarily as a result of changes in policy, not crime rates, so too have declines reflected changes in both policy and practice. These have included such measures as drug policy sentencing reforms, reduced admissions of technical parole violators to prison, and diversion options for persons convicted of lower-level property and drug crimes.