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Guangzhen Wu [email protected], Francis D. Boateng, and Xiaodong LangView all authors and affiliations


An ongoing debate exists about the implications of recreational marijuana legalization to public safety. One important public concern is how recreational marijuana legalization may affect crime in neighboring states that have not legalized. Based on Uniform Crime Report (UCR) data from 2003 to 2017, this study used difference-in-differences (DID) analysis to examine the potential spillover effect of recreational marijuana legalization in Colorado and Washington State, with a special focus on the examination of the changes in the rates of a variety of crimes in the border counties of neighboring states relative to the nonborder counties in these states following Colorado’s and Washington’s legalization. Results provide some evidence suggesting a spillover crime reduction effect of legalization, as reflected by the significant decreases in the rates of property crime, larceny, and simple assault in the Colorado region that includes six neighboring states. Results also suggest that the effects of marijuana legalization on crime in neighboring states vary based on crime type and state.