مقایسهٔ روش‌ها

	Pollard Decomposition	Arriaga Decomposition
حوزه	جمعیت‌شناسی	جمعیت‌شناسی
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	1982	1984
پدیدآور	John H. Pollard	Eduardo E. Arriaga
نوع	Age-specific decomposition of a difference in life expectancy	Age-specific decomposition of a difference in life expectancy
منبع بنیادین	Pollard, J. H. (1982). The expectation of life and its relationship to mortality. Journal of the Institute of Actuaries, 109(2), 225–240.	Arriaga, E. E. (1984). Measuring and explaining the change in life expectancies. Demography, 21(1), 83–96.
نام‌های دیگر	Pollard's Method, Pollard Life Expectancy Decomposition, Continuous Age Decomposition of Life Expectancy	Arriaga's method, Life-expectancy decomposition, Age decomposition of life expectancy, Arriaga Ayrıştırması
مرتبط	4	4
خلاصه	Pollard's decomposition breaks a difference in life expectancy between two populations into additive contributions from each age, showing exactly how much of the gap is due to mortality differences at infancy, in midlife, or in old age. John Pollard derived a continuous-age formula expressing the life-expectancy difference as an integral of the age-specific mortality-rate difference weighted by life-table functions. Because the contributions sum exactly to the total gap and can be further split by cause of death, the method is a standard tool for explaining why one population outlives another.	Arriaga decomposition is a demographic technique that breaks down the difference in life expectancy between two life tables — two countries, two time points, or two groups — into the contributions of mortality change at each age. Introduced by Eduardo Arriaga in 1984, it tells the analyst not just that life expectancy rose or fell, but exactly which ages drove the change, separating the direct effect of mortality change within an age interval from the indirect effect of the extra survivors that change passes on to older ages.