Project Summary COVID-19 threatens to exacerbate the ongoing opioid epidemic in the United States, but the pandemic has also provided an opportunity to experiment with changes in how opioid treatment services are delivered around the country. The current pandemic has resulted in a flurry of unprecedented policy measures, and it is crucial to understand the impact that rapid changes in law, regulation, and policy are having on individuals with opioid use disorder (OUD), particularly those involved with the criminal justice system. Deploying law to support, rather than hinder access to treatment requires evidence of which legal levers help and which hurt, and a clear mapping of the state of the law in every applicable jurisdiction. Legal epidemiology – the scientific study and deployment of law as a factor in the cause, distribution, and prevention of disease and injury in a population – provides an innovative framework to understanding the positive, negative, and incidental effects of these policy changes on population health. The research team will use legal epidemiology and policy surveillance methods to collect and systematically code laws, regulations, executive orders, Medicaid waivers, and other opioid- related policies relevant to the criminal justice system during the COVID-19 pandemic. The legal data will be published and freely available for download for all users, including JCOIN network members, to evaluate the impact of these evolving legal measures on health outcomes over time. 1