MICHELE: The Computation of Healthy Life Expectancy from Mortality Schedules

Healthy life expectancy is conventionally computed by combining life-table mortality with independently observed health information. This paper proposes an alternative approach that computes healthy life expectancy from mortality schedules alone. Building on the empirical regularities that adult mortality follows Gompertz's law and that mortality is related to the frailty index by a power law, we introduce Mortality-Implied Continuous Health-Equivalent Life Expectancy (MICHELE). The framework is validated using the Health and Retirement Study, where MICHELE closely reproduces directly observed Continuous Health-Equivalent Life Expectancy, and using Healthy Life Expectancy from the Global Burden of Disease Study, where mortality-implied health weights explain almost all age-related variation in disability-based health weights. The results suggest that mortality schedules contain substantially more information about the biological aging process underlying healthy longevity than has generally been recognized and provide a simple approach for estimating healthy life expectancy when comparable health data are unavailable.