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Tracing the effects of reducing penalties on crime and prosecution

NCJ Number
Journal of Criminal Justice Volume: 75 Dated: July-August 2021
Date Published

This study examined the impact on crime and prosecution of California’s legislative changes intended to reduce overcrowding in prisons.


To reduce overcrowding in prisons, California made two legislative changes: Assembly Bill 109 (AB 109) in 2011 and Proposition 47 (Prop 47) in 2014. Evidence suggests they were successful at reducing incarceration; however, there is limited understanding of how each of these changes, individually, affected crime and prosecution. Using data from multiple criminal justice agencies in the city of Los Angeles, California, the present study used interrupted time series analysis to examine the effects of AB 109 and Prop 47 on level and trend changes in burglary, motor vehicle theft (MVT), larceny/theft, financial crimes and their corresponding felony and misdemeanor prosecutions. Although some offenses exhibited statistically significant level and/or trend changes associated with one or both legislative changes, the impacts of AB 109 and Prop 47 on crimes and prosecutions are generally small. Results indicate AB 109 and Prop 47, individually, have had slightly different effects on crime and prosecutions for property and financial offenses. The study concluded that neither AB 109 nor Prop 47 sparked the immediate and large increases in crime forecasted by critics. Policymakers in other states considering instituting similar changes to reduce their prison populations should be encouraged by these results. (publisher abstract modified)

Date Published: January 1, 2021