An Iteration Technique for Estimating Survival Probabilities at Ages beyond Five

Subrata Lahiri, International Institute for Population Sciences (IIPS)

This study presents a method for estimating an appropriate set of survival probability (p-values) over various ages which is not only consistent with the given set of 5-year cumulative life table survival ratios (5-cum-LSRs), defined by the ratios T(x+5)/T(x), but also satisfies the usual properties and depicts the true trends of life table p-values over ages. Two approaches have been proposed in this paper for estimating survival probability at various quinquennial ages based on a given set of 5-cum-LSR values at various quinquennial ages -- one makes use of a chain relationship between two survival probabilities in the adjacent age-intervals for a given set of 5-cum-LSRs, and the other one is based on an iterative procedure under various assumptions of the l(x) curve. Empirical investigations of the approaches based on model life tables show that the estimated p-values beyond age five obtained by this method are almost identical to the true one.