Projecting Age-Specific Death Probabilities at Advanced Ages Using the Mortality Laws of Gompertz and Wittstein

Abstract

In this paper, death probabilities derived from the Gompertz and Wittstein models are used to project mortality at advanced ages beginning at the age of 101 years. Life table data of Germany from 1871 to 2012 serve as a basis for the empirical analysis. Projections of the death probabilities and life table survivors will be shown. The increase of the death probabilities slows down at very old ages. Finally, Wittstein´s formula will be regarded as a distribution function. Its reversed hazard rate function, which will be derived together with the median and the modal value, will clarify the significance of the parameters of the Wittstein distribution.