A cubic model for graduation of life tables

Karol Pastor, Comenius University Bratislava

The calculation of the probabilities of dying for ages greater than 85 (e.g. at the end of the life table) is usually performed by the extrapolation of graduated values following Gompertz - Makeham law of mortality (the King - Hardy method). Nowadays, several authors have observed that this method overestimates the real probabilities. That is why other methods of extrapolation have been examined (Kannisto, Koschin and others). The purpose of the paper is to present a graduation method, which in calculation process fits the logarithm of specific mortality rates by a cubic parabola. Moreover, alternative ways of closing the life table are proposed.