Replication Data for: Exploring the effect of Colorado's recreational marijuana policy on opioid overdose rates

How has the legalization of recreational marijuana shaped opioid overdose deaths in Colorado? While prior research has examined the effects of medical cannabis laws, less is known about the public health consequences of broader marijuana policy liberalization. In this study, I use the synthetic control method to estimate the effect of Colorado’s 2014 policy change, comparing the state to a data-driven composite of similar states from 1999 to 2017. Using CDC WONDER data, I construct a counterfactual scenario in which Colorado did not legalize recreational cannabis, incorporating relevant predictors of opioid mortality. I supplement this approach with a difference-in-differences estimate and conduct placebo inference tests to assess robustness. The results suggest a 5% decline in opioid overdose deaths following legalization, but this effect is not statistically significant. These findings offer limited evidence that recreational marijuana access meaningfully reduced opioid-related mortality in Colorado, underscoring the need for more nuanced evaluations of drug policy reform.