Longer life but worse health? Measurement and dynamics.

A number of recent cross-sectional studies of longevity and health among the elderly have concluded that recent positive trends in the prolongation of life have not been matched by similar trends in the extension of healthy life. This paper challenges that pessimistic conclusion by examining conceptual issues related to the measurement and dynamics of the mortality-disability process. It uses data from the 1986 Longitudinal Study of Aging (U.S. Department of Health and Human Services, 1988) to illustrate its principal points.