Σύγκριση μεθόδων

	Pollard Decomposition	Kitagawa Decomposition
Πεδίο	Δημογραφία	Δημογραφία
Οικογένεια	Process / pipeline	Process / pipeline
Έτος προέλευσης	1982	1955
Δημιουργός	John H. Pollard	Evelyn M. Kitagawa
Τύπος	Age-specific decomposition of a difference in life expectancy	Arithmetic decomposition of a difference between two summary rates
Θεμελιώδης πηγή	Pollard, J. H. (1982). The expectation of life and its relationship to mortality. Journal of the Institute of Actuaries, 109(2), 225–240.	Kitagawa, E. M. (1955). Components of a difference between two rates. Journal of the American Statistical Association, 50(272), 1168–1194.
Εναλλακτικές ονομασίες	Pollard's Method, Pollard Life Expectancy Decomposition, Continuous Age Decomposition of Life Expectancy	Components-of-difference method, Rate decomposition, Standardization decomposition, Kitagawa Ayrıştırması
Συναφείς	4	4
Σύνοψη	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.	Kitagawa decomposition is a demographic technique that splits the difference between two summary rates — such as two crude death rates, birth rates, or prevalence figures — into the part attributable to differences in the underlying group-specific rates and the part attributable to differences in population composition. Introduced by Evelyn Kitagawa in 1955, it answers whether a gap between two populations reflects genuinely different risks or merely a different age (or other) structure.