This report is the result of over a year of work by the International Expert Group on Drug Policy Metrics, convened by the Conflict Prevention and Peace Forum (CPPF) and the International Peace Institute (IPI). This project reflects the growing chorus of voices calling for a better system for measuring the impact of drug policy. A first informal meeting took place at IPI in New York on the margins of the UN General Assembly special session on the world drug problem in April 2016. After securing funding, the group met for a two-day-long meeting at CPPF in January 2017. The group then had a third meeting at IPI’s office in Vienna in March 2017, on the margins of the annual meeting of the UN Commission on Narcotic Drugs.