In this letter to the Advisory Committee on Data for Evidence Building, Paul Decker describes the challenges and opportunities inherent in using data and evidence to support informed decision making. He outlines key factors that are paving the way toward progress at the federal level and within state, and local governments. This includes: opportunities to build states’ capacity to collect, store, and analyze data; the advantages of a National Secure Data Service; high-impact data uses for evidence-based policymaking; and digital tools to help governments overcome challenges in building and using evidence.