قارن الطرق

	Siler Mortality Model	Heligman-Pollard Model
المجال	علم السكان	علم السكان
العائلة	Regression model	Regression model
سنة النشأة	1979	1980
صاحب الطريقة	William Siler	Larry Heligman & John H. Pollard
النوع	Parametric three-component competing-hazard model of the full age pattern of mortality	Parametric whole-lifespan mortality law
المصدر التأسيسي	Siler, W. (1979). A competing-risk model for animal mortality. Ecology, 60(4), 750–757.	Heligman, L., & Pollard, J. H. (1980). The age pattern of mortality. Journal of the Institute of Actuaries, 107(1), 49–80.
الأسماء البديلة	Siler Model, Siler Competing-Risk Model, Five-Parameter Siler Hazard	Heligman-Pollard Mortality Law, Eight-Parameter Mortality Model, HP Mortality Model, Heligman-Pollard Ölümlülük Modeli
ذات صلة	4	4
الملخص	The Siler model is a parametric description of the entire age pattern of mortality, from birth to extreme old age, built as the sum of three competing hazards: a high but rapidly declining risk in early life, a roughly constant background risk through the prime adult years, and an exponentially rising risk of senescence. With just five parameters it reproduces the characteristic U-shaped (or bathtub) mortality curve seen across humans and many animal species. Introduced by William Siler in 1979 for animal mortality, it has become a standard tool in paleodemography, anthropological demography, and comparative life-history studies where a smooth full-lifespan mortality law is needed.	The Heligman-Pollard model is an eight-parameter parametric law that describes the age pattern of mortality across the entire human lifespan in a single equation. Introduced by Larry Heligman and John Pollard in 1980, it represents the odds of dying at each age as the sum of three additive components — a rapidly declining childhood term, a young-adult accident hump, and an exponentially rising senescent term — capturing the full characteristic shape of the mortality curve from birth to old age.