“As mayor of Salt Lake County, a job in which I represent the 1.1 million people who live in the Greater Salt Lake metro area, my job is to ask, What are we spending our money on? What is working for our residents — or not? What programs should be tweaked or stopped altogether? How can we do better? And how will we know if our efforts are working?” writes Mayor Ben McAdams in this contribution to Innovations. McAdams discusses his experience with Pay for Success, including Salt Lake City’s first Pay for Success initiation in early education and later Pay for Success projects for recidivism and homelessness, and focuses on key lessons learned including the importance of political will, partnerships, and reliable sources of repayment to attract lenders.