قارن الطرق

	Abridged Life Table	Healthy Life Expectancy Decomposition
المجال	Social Epidemiology	Social Epidemiology
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1984	2004
صاحب الطريقة	Chin Long Chiang; Samuel Preston, Patrick Heuveline & Michel Guillot	Wilma J. Nusselder & Caspar W. N. Looman; Daniel F. Sullivan
النوع	Demographic estimation pipeline for mortality and survivorship	Demographic decomposition pipeline for a health-expectancy difference
المصدر التأسيسي	Chiang, C. L. (1984). The Life Table and Its Applications. Malabar, FL: Robert E. Krieger Publishing. ISBN: 9780898745702	Nusselder, W. J., & Looman, C. W. N. (2004). Decomposition of differences in health expectancy by cause. Demography, 41(2), 315-334.
الأسماء البديلة	Abridged Life Table Method, Grouped-Age Life Table, Chiang Life Table, nMx to nqx Life Table	Health Expectancy Decomposition, Nusselder-Looman Decomposition, Decomposition of Disability-Free Life Expectancy, Mortality and Disability Decomposition of Health Expectancy
ذات صلة	3	4
الملخص	The abridged life table is the workhorse of demography and population health for summarizing the mortality experience of a population in a single, age-grouped table. Instead of a single-year (complete) life table, it works on broad age intervals — typically <1, 1-4, then five-year groups up to an open-ended oldest interval — which makes it robust when deaths or populations in single years of age are sparse or noisy. The construction propagates a small set of inputs, the age-specific death rates nMx, through a chain of columns: the probability of dying nqx, the survivors lx, the deaths ndx, the person-years lived nLx and Tx, and finally life expectancy ex. Chiang's 1984 treatment supplied the standard estimator and the fraction-of-interval term ax that controls how person-years are allocated within each interval, while Preston, Heuveline and Guillot's 2001 textbook codified the modern pipeline used across demography and epidemiology.	Healthy (or disability-free) life expectancy combines how long people live with how much of that life is spent in good health, and differences in it between groups or over time reflect two distinct forces: changes in mortality and changes in the prevalence of disability. Healthy-life-expectancy decomposition separates these forces. Building on the Sullivan method — which weights life-table person-years by the age-specific share of life lived without disability — Wilma Nusselder and Caspar Looman's 2004 method splits the gap in health expectancy between two populations into an additive mortality component and a disability component for each age, and can further attribute each to specific causes. This resolves the central interpretive ambiguity of health expectancy: a population can have higher healthy life expectancy because its people die later, because they are less disabled at each age, or both, and only a decomposition can tell which.