Shifting Mortality: Inevitable or Anomaly?

Sarah Zureick, University of California, Berkeley

While shifting mortality was conceptualized as a shift in mortality rates across age, trends in variability of age at death are used to evaluate whether or not a country is exhibiting signs of shifting mortality. In this paper, I reexamine the relationship between mortality change and trends in variability age of death in order to evaluate whether shifting mortality is an inevitable outcome of the mortality transition. Through simulation exercises, perturbation analysis, and decomposition analysis, I arrive at a better understanding of how initial mortality conditions interact with the age-pattern of mortality change to produce mortality compression, expansion, or shifting. I find that proportional mortality change that is fixed across ages does not necessarily lead to a parallel shift in the death distribution. In addition, I demonstrate that certain initial mortality conditions are particularly primed for compression.