The COVID-19 Pandemic, Prison Downsizing, and Crime Trends

California has fundamentally reformed its criminal justice system. Since 2011, the state passed several reforms which reduced its massive prison population. Importantly, this decarceration has not harmed public safety as research finds these measures had no impact on violent crime and only marginal impacts on property crime statewide. The COVID-19 pandemic furthered the state's trend in decarceration, as California reduced prison and jail populations to slow the spread of the virus. In fact, in terms of month-to-month proportionate changes in the state correctional population, California's efforts to reduce overcrowding as a means to limit the spread of COVID-19 reduced the correctional population more severely and abruptly than any of the state's decarceration reforms. Although research suggests the criminal justice reforms did not threaten public safety, there is reason to suspect COVID-mitigation releases did. How are COVID-19 jail downsizing measures and crime trends related in California, if at all? We address this question in the current study. We employ a synthetic control group design to estimate the impact of jail decarceration intended to mitigate COVID-19 spread on crime in California's 58 counties. Adapting the traditional method to account for the "fuzzy-ness" of the intervention, we utilize natural variation among counties to isolate decarceration's impact on crime from various other shocks affecting California as a whole. Findings do not suggest a consistent relationship between COVID-19 jail decarceration and violent or property crime at the county level.