Past and Recent Attempts to Model Mortality at All Ages
In demography, model life tables have played an increasingly important role in indirect estimation, population projections, simulations and for other purposes where there is a need for a model of mortality at all ages. In actuarial science, model life tables have played a subdued role because laws of mortality, i.e., parametric functions that give a good fit to empirical mortality curves, are a better means of graduation than discrete morality representations. Most laws of mortality are partial in the sense that they apply only to a broad age group and not to all ages. This paper focuses on three laws of mortality that apply to all ages. Two of them were developed by the actuaries Thiele and Wittstein in the late 19th century. The third, developed by Heligman and Pollard, is of recent origin. The three laws are discussed with references to Scandinavian mortality data. The results suggest that the most recently proposed law can be used for generation of model life tables, for making population projections, simulations, and other statistical work where there is a need for a realistic model of human mortality.
Laws of mortality; model life tables; indirect estimation; normal places; least squares minimization; population projections.