Initiative 502, passed by voters in 2012, authorizes the regulation, sale and taxation of marijuana for adults over the age of 21. Funding is provided for a contract with the Washington State Institute for Public Policy to conduct a cost-benefit evaluation of implementation of I-502, as required by the initiative. A preliminary report is due to the Legislature by September 1, 2015, and the first final report is due by September 1, 2017.