Evaluating and creating rigorous public policy—ideas rooted in credible data and designed to improve lives and strengthen communities—requires a broad portfolio of tools. Policy development occurs in multiple states and extends over time. Policymakers need evidence at each step in order to help them

• diagnose problems and underlying causes;
• design new policy options and assess the likely effects of alternatives;
• demonstrate and evaluate the impacts of new, model programs;
• monitor program implementation, measuring costs and performance and their sensitivity to different settings; and
• evaluate the long-term impacts and cost-effectiveness of existing programs.

No single research methodology or dataset can deliver that wide variety of evidence. Instead, we need a portfolio of rigorous instruments to advance evidence-based policy effectively.