Association for Public Policy Analysis & Management

The potential effect of cannabis legalization on crime is central to arguments made by those in favor and those against legalizing recreational sales. In this paper, we use a synthetic control model to evaluate whether legalization impacted violent and property crime rates in Colorado and Washington, the first states to legalize recreational sales in the United States. We develop synthetic controls based on states which, under a weighted average, have similar pre-legalization crime rates to those of Colorado and Washington and which are comparable to those states across a set of covariates related to crime. Our findings suggest the legalization of recreational sales may have reduced violent crimes in Washington. In 2017, the last year of observation, Washington experienced 7.14 fewer violent crimes per 100,000 people than the synthetic control, the equivalent of 529 fewer violent crimes per year. Placebo analyses, however, prevent us from concluding there is a causal effect. The synthetic controls for the three other outcomes—property crime in Washington, and property and violent crime in Colorado—were poor fits, and we were therefore unable to estimate the effect of legalization on those outcomes. In future versions of this paper, we hope to include an additional covariate based on opioid use, among other improvements.