The National Bureau of Economic Research (NBER) has an ongoing project on the foundations of disability decline, what might be done to extend and accelerate future improvements in functional ability, and how the benefits of disability decline can be evaluated in economic terms. A group of economists, demographers, epidemiologists, and physicians are examining the causes and characteristics of past disability trends to identify the core foundations of disability decline, and to think about improving functional ability in the future. Five research strategies have been identified: 1) Characterizing disability decline; 2) Pathways to disability; 3) Health conditions that lead to disability; and 4) Economic and labor market implications of disability decline.