EFFECTS OF EXTRA CHANCES TO LIVE ON LIFE TABLE FUNCTIONS

A decline in mortality can be described as a process according to which the earlier forces of mortality become what has been defined here as the forces of debility. The main thesis is that individuals contract debilitating conditions now with the same force that used to result in deaths in the past. The difference in the two situations is that in the latter period, a certain proportion of the population can recover and thus escape death. Based on these assumptions, the relationships between the initial and the resulting life table functions have been developed in this paper. Among other things, the relative gain in life expectancy has been found to be inversely related to its initial value. Further, interesting results are obtained when a fixed proportion of the population can manage to survive a debilitating condition only once, only twice and so on. The limiting situation has been found to be equivalent to one in which the initial forces of mortality at all ages are reduced by a constant proportion. © 1979.