New Definition Suggested for Old Age

A new study reconceptualizes population aging, providing a toolbox of methodologies for demographers to better understand the impacts of an aging population on society.

Researchers at the International Institute for Applied Systems Analysis (IIASA; Laxenburg, Austria) and the Wittgenstein Center for Demography and Global Human Capital (Vienna, Austria) provide a framework for measuring aging that is based on characteristics of people that change with age, including life expectancy, health, cognitive function, and other measures. They derived a structured mathematical approach, providing empirical examples of the insights it offers, drawing on data from West Germany, Japan, Russia, and the United States.

Demographers have not traditionally used such measures in studies of population and society, and have instead used chronological age as a proxy for those characteristics. But as lifespans get longer, the same age no longer correlates with the same level of health and other such characteristics. This “characteristics approach”, set out in the article, encompasses multiple features of population aging, yielding new measures that can better inform both demographic analysis and public policy debate. The study was published on December 5, 2013, in Population and Development Review.

“For different purposes we need different measures; aging is multidimensional. Your true age is not just the number of years you have lived, it also includes characteristics such as health, cognitive function, and disability rates,” said study coauthor IIASA researcher Sergei Scherbov, PhD. “We use to consider people old at age 65. Today, someone who is 65 may be more like someone who was 55 forty-fifty years ago in terms of many important aspects of their lives.”

“One new metric, called prospective age, flips around age,” added Dr. Scherbov. “We measure age not as years since birth, but as distance from expected death. That means that as life expectancies increase, people become younger. This method sets the threshold for ‘old’ at 15 years to projected life expectancy.”

In Europe and other developed regions of the world, life expectancy has increased significantly in recent decades, and continues to increase. As people live longer, they also stay healthier longer. But since traditional measures of age have not changed, a growing section of the population gets categorized as old just because they have reached the magic age of 65. This somewhat arbitrary measure has major implications for pensions, for health care systems, and for the labor force.

Related Links:
International Institute for Applied Systems Analysis
Wittgenstein Centre for Demography and Global Human Capital