"Preliminary look at racial disparities in select counties of Washington
"The Crime, Cannabis & Police Research Group at Washington State University used preliminary data from a Department of Justice funded study to compare white vs. Black arrests.11 Latinos were not included in the analysis, because of difficulties measuring ethnicity in arrest data. Their main preliminary findings are that after legalization in Washington, African Americans/Blacks continue to be disproportionally arrested for the possession and selling of marijuana when compared to whites. Though the disparity in marijuana possession between African American/Blacks and whites was reduced slightly after legalization, the disparity for selling marijuana has more than doubled since legalization.
"Local trends
"While statewide studies have the ability to control for individual law enforcement agencies or police departments, monitoring trends in marijuana-related crimes within a local police department can provide details of violations that statewide data systems do not. For example, violations for public consumption of marijuana cannot be directly queried from state-derived data; however, local law enforcement agencies and municipal courts maintain details on the nature of the crime that would indicate whether someone was ticketed for public consumption vs. possession or a different drug-related charge. One example of the potential of local data to explore issues of criminal justice can be made using data from the Seattle Police Department (SPD). A 2015 report for the Seattle Community Police Commission showed a disproportionate number of citations for marijuana public consumption issued to African Americans/Blacks in Seattle.12 Using local police department data is key to understanding differences in the implementation and enforcement of polices pertaining to the legalization of marijuana."
Firth C. Marijuana Legalization in Washington State: Monitoring the Impact on Racial Disparities in Criminal Justice. Alcohol & Drug Abuse Institute, University of Washington, June 2018.