The NBER Retirement Research Center is funded by the Social Security Administration as part of its Retirement Research Consortium. The central goal of the Center is to conduct research that can be used to inform future Social Security policy. Underlying the substantive research agenda of the Center are three key themes: (1) That reform must recognize the changing and uncertain environment in which the Social Security system will operate. (2) That several alternative routes to sustainable solvency should be explored. (3) That the potential routes to solvency should be evaluated for "resiliency" to uncertain future demographic, economic, and social trends.