Prospective longevity: A new vision of population aging

A new pathbreaking book by IIASA researchers offers an opportunity to rethink how we define and measure population aging to inform better policies for future societal and economic health.

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The seminal book titled Prospective longevity: A new vision of population aging, redefines the current view of population aging by showing how we can generate better demographic estimates to inform better policies. It provides a new way to measure population aging and show that aging can be measured not only using how many years we have lived, but also through other characteristics, such as the number of years we have left to live, our disabilities, and our cognitive abilities. The analysis allows for a more precise quantification of the extent of population aging and reveals new aspects that were previously not observed. Today’s 65-year-olds, for example, have different characteristics from those who were born decades ago, and tomorrow’s 65-year-olds will likely also be different from today’s. Counting the present day 65-year-olds as an economically inactive person can mislead the classification of the burden of old-age dependency in a country.

Most fundamentally, the idea is to minimize the overreliance on chronological age in the study of population aging. How functional people are depends on what they can do and on their health, not merely on how many years they have lived. The research deals with measuring population aging, including reinterpreting its history and likely future. The authors discuss aging and public pensions, as well as questions about whether population aging will be faster or slower as life expectancy increase speeds up, along with a host of other interesting questions.

IIASA researchers have been working on the topic of population aging for over a decade and have developed a new paradigm in conceptualizing population aging – the Characteristics Approach – as part of the Reassessing Aging from a Population Perspective (Re-Aging) project funded by the European Research Council. The hallmark of the approach is the consistent use of changing characteristics of people temporally and spatially. The approach has strong implications for both research and policy and is already being used by the UN to redefine aging for most countries in the world. The UK Office of National Statistics has also produced an important report using the authors’ research as part of an innovative analysis of population health.


[1] Sanderson W & Scherbov S (2019). Prospective Longevity: A New Vision of Population Aging. Cambridge, MA: Harvard University Press.

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