Demography, Vol. 31, No.2, May 1994 Estimating Increment-Decrement Life Tables with Multiple Covariates from Panel Data: The Case of Active Life Expectancy* Kenneth C. Land Department of Sociology and Center for Demographic Studies and Center for Aging and Human Development Duke University Durham, NC 27708-0088 Jack M. Guralnik Epidemiology, Demography, and Biometry Program National Institute on Aging 7201 Wisconsin Avenue Bethesda, MD 20892 Dan G. Blazer Office of Medical Education Box 3005 Duke University Medical Center Durham, NC 27710 A fundamental limitation of current multistate life table methodology-evident in recent estimates of active life expectancy for the elderly-is the inability to estimate tables from data on small longitudinal panels in the presence of multiple covariates (such as sex, race, and socioeconomic status). This paper presents an approach to such an estimation based on an isomorphism between the structure of the stochastic model underlying a conventional specification of the increment-decrement life table and that of Markov panel regression models for simple state spaces. We argue that Markov panel regression procedures can be used to provide smoothed or graduated group-specific estimates of transition probabilities that are more stable across short age intervals than those computed directly from sample data. We then join these estimates with increment-decrement life table methods to compute group-specific total, active, and dependent life expectancy estimates. To illustrate the methods, we describe an empirical application to the estimation of such life expectancies specific to sex, race, and education (years of school completed) for a longitudinal panel of elderly persons. We find that education extends both total life expectancy and active life expectancy. Education thus may serve as a powerful social protective mechanism delaying the onset of health problems at older ages. During the past three decades, much attention has focused on the development of health status measures that combine mortality and disability data. In particular, building on * Data analyzed in this study are from the Duke Established Populations for Epidemiologic Studies of the Elderly, which were established pursuant to NIA Contract N02-AG-I-2102. The content of this publication does not necessarily reflect the views or policies of the U.S. Department of Health and Human Services. nor does Copyright © 1994 Population Association of America 297 Downloaded from http://read.dukeupress.edu/demography/article-pdf/31/2/297/891962/297land.pdf by guest on 12 December 2021