Faster Increases in Human Life Expectancy Will Lead to Slower Population Aging

Warren C. Sanderson, Stony Brook University, State University of New York (SUNY)
Sergei Scherbov, Wittgenstein Centre (IIASA, VID/ÖAW, WU) and International Institute for Applied Systems Analysis (IIASA)

Counterintuitively, faster increases in human life expectancy will lead to slower population aging. The conventional view that faster increases in human life expectancy will lead to faster population aging is based on a specific definition of who is old that does not take the changing characteristics of people into account. But the relevant characteristics of people do change over time and differ significantly across countries. In this paper, we show that faster increases in life expectancy will lead to slower population aging when changes in those characteristics are taken into account. Among other things, this finding affects the assessment of the speed at which countries will age and the interpretation of forecasts of aging. Our results suggest that many of the challenges of population aging will be harder not when life expectancy growth is faster, but when it is slower.