Adjusting life expectancy to account for disability in a population: A comparison of three techniques

Sullivan (1971) first suggested weighting life expectancy (LE) to account f or the health of a population using a single indicator. Known as disability free life expectancy (DFLEs), this measure was somewhat limited due to a o verly simplistic weighting scheme. Its introduction, however, spurred the d evelopment of a whole new class of measures known as health expectancy indi cators. One of the first, disability-adjusted life expectancy (DALEs) (Wilk ins and Adams, 1983), identified the period of time in a particular level o f disability and weighted each level accordingly. While the weighting allow ed for a health related quality-of-life distinction to be introduced into t he DALE measure, the weights, by level of disability, were arbitrarily chos en and fixed for all ages and gender. To overcome this limitation, a health -adjusted life expectancy (HALE) was developed based in large part on the D ALE methodology but utilizes more refined weights. The McMaster Health Util ity Index Mark III (HUI3)) scores health on a continuum from 0 to 1 and whe n included on a national health survey, provides estimates that reflect imp ortant age, gender, and socio-economic factors. All three measures were cal culated for the years 1986, 1991, and 1994 (household and institutional pop ulations). Analysis revealed that HALEs were more appropriate for policy pu rposes due to their ability to account for indirect morbidity in both a dis abled and non-disabled population.