Emerging Rectangularization of the Survival Curve in India: Measuring Age-Specific Mortality Contributions

Sarbani Thakur, University of Chicago

The Indian population, characterized by increased life expectancy and reduced variability in age-at-death, signifies the onset of Rectangularization of the Survival Curve (RSC). This shift, toward a more uniform age-at-death distribution, remains under-explored in developing nations. This study aims to empirically examine the RSC hypothesis in India and evaluate the contribution of age-specific mortality rates (ASMRs) to this process. By generating 160 complete life tables derived from abridged life tables of SRS, Keyfitz’s H-a metric for measuring RSC has been estimated. Both graphical and empirical findings substantiate the inverse relationship between variability in the age-at-death distribution and the survival function, emphasizing how the survival curve shifts rightward due to unimodality in death distributions at higher ages. The paper seconds the shifting mortality hypothesis while refuting the concept of 'looming limits' of life expectancy. The point of fastest decline (inflection point) on the survival curve occurs at age 80 for both sexes in India, indicating a shift in mortality patterns toward older ages. The study attempts to extend knowledge by forecasting the years of improvements in the survival curve’s verticality while highlighting the importance of its horizontality to better explain the desirability of rectangularization of survival curve in a country.

Keywords: Mathematical demography , Decomposition analysis, Mortality and Longevity, Population Ageing

See paper.