To quantify the impact of cannabis prohibition and the “War on Drugs,” it was necessary to first conceptualize how this could be measured using available data. Prior research demonstrates that enforcement of drug prohibition has resulted in disproportionately high numbers of arrests and incarceration for Black and Latino individuals. These disparities persist despite cannabis decriminalization in Massachusetts in 2008, medical legalization in 2012, and adult-use legalization in 2016. There are strong correlations between poverty and involvement in drug selling and/or drug use; and after incarceration, many individuals face steep challenges to gaining legal employment, which can set up cycles of poverty that last generations. The disproportionate impact (DI) score, therefore, included four primary factors at a geographic-level: Drug arrests, including: (1) average annual number of drug arrests; and (2) average annual rate of drug arrests per 100,000 population; (3) percent of people living in poverty (“economic deprivation”); and (4) the percent of residents who report Black and/or Latino race/ethnicity (“racial and ethnic composition”). These factors were examined for 295 municipalities across Massachusetts, as well as for 305 census tracts in the state’s five largest cities (Boston, Cambridge, Lowell, Springfield, and Worcester).