Estimating healthy life expectancies using longitudinal survey data: methods and techniques in population health measures.

Objective-Summary measures of population health are statistics that combine mortality and morbidity to represent overall population health in a single index. Such measures include healthy life expectancy, also called disability-free life expectancy and active life expectancy. Healthy life expectancy can be calculated using cross-sectional or longitudinal survey data. This report presents a comprehensive discussion of a method for calculating healthy life expectancy using data from longitudinal surveys. Methods-Healthy life expectancies are calculated using the multistate life table model. Expected life in various states of health is estimated using data from the Second Longitudinal Study of Aging and the Medicare Current Beneficiary Survey to illustrate the calculation of the statistics and the discussion of data and methodology related issues. Results-The study shows that estimating summary measures of population health using longitudinal survey data provides the opportunity of using incidence rather than prevalence rates. Health measures estimated based on incidence reflect the most recent health status of the population. Models that use longitudinal survey data measure transitions from good to poor health as well as poor to good health. That is, the models account for recovery from morbidity or illness. Longitudinal survey data canalsobeusedtocalculate healthy or active life expectancies by initial health states.