Probabilistic population aging

PLoS One. 2017 Jun 21;12(6):e0179171. doi: 10.1371/journal.pone.0179171. eCollection 2017.

Abstract

We merge two methodologies, prospective measures of population aging and probabilistic population forecasts. We compare the speed of change and variability in forecasts of the old age dependency ratio and the prospective old age dependency ratio as well as the same comparison for the median age and the prospective median age. While conventional measures of population aging are computed on the basis of the number of years people have already lived, prospective measures are computed also taking account of the expected number of years they have left to live. Those remaining life expectancies change over time and differ from place to place. We compare the probabilistic distributions of the conventional and prospective measures using examples from China, Germany, Iran, and the United States. The changes over time and the variability of the prospective indicators are smaller than those that are observed in the conventional ones. A wide variety of new results emerge from the combination of methodologies. For example, for Germany, Iran, and the United States the likelihood that the prospective median age of the population in 2098 will be lower than it is today is close to 100 percent.

MeSH terms

  • Adult
  • Age Factors
  • Aging*
  • China
  • Female
  • Germany
  • Humans
  • Iran
  • Life Expectancy / trends*
  • Male
  • Middle Aged
  • Population Dynamics*
  • Prospective Studies
  • Time Factors
  • United States

Grants and funding

We thank the Population Division of the United Nations for providing access to a subset of trajectories of probabilistic population projections and associated abridged life tables based on the World Population Prospects: The 2015 Revision. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement no ERC2012-AdG 323947-Re-Ageing. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The views and opinions expressed in this paper are those of the authors and do not necessarily represent those of the United Nations.