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I think there's an unwritten law that every article or political discussion about population aging must start with some scary statistics to frame the discussion. So here are a few From the United Nations. Between 2015 and 2050, the proportion of the world's population over the age of 60 will nearly double from 12 percent to 22 percent. In 2021, there were 17 people aged 65 and over for every 100 people aged 20 to 64 (this is called the “old-age dependency ratio”); By 2050, there will be 29 per 100.
So far, so familiar. But what if these statistics aren't a useful framework for discussion? What if “65 and older” is a bad definition of “old age”? In fact, what if chronological age isn't a good measure of aging at all?
The only thing a person's chronological age tells you is how many years they have lived. Policymakers worry about statistics like those mentioned above because they use chronological age as an indicator of other things that worry them, such as the number of vulnerable or sick people who will need health or social care in the future, or their economic and social status. The financial impact of fewer workers and more retirees, etc.
This would be fair enough if chronological age were a reasonable indicator of all these things, but is it? A paper Economists Rainer Kocchi, David Bloom and Andrew Scott, published last month, argue that relying on chronological age is “incomplete at best, and misleading at worst,” because it provides “only limited information about the aging process.”
Obviously, people of the same age can vary greatly in terms of how weak or sick they are. Using data from the United States and England on the physiological capabilities of people over 50, Cucci, Bloom and Scott found that the healthiest 10% of the population at 90 years of age approach the same level of frailty as the average 50-year-old. .
Average health and fitness levels by chronological age can also change over time. In the United Kingdom, for example, 70-year-old women in 2017 showed roughly the same levels of poor general health as 60-year-old women in 1981. according to Office for National Statistics.
If you use chronological age as an indicator of when people stop working, this also varies a lot by country and over time (and is of course particularly sensitive to changes in state pension ages). How important is the “Old Dependency Ratio” which classifies people over 65 as “dependents” in a country like the UK, where the proportion of working people has risen from 27 per cent in 2014 to 40 per cent in 2024?
As Warren Sanderson and Sergei Scherpov, leading researchers in this field, put it, I put it: “Should a 60-year-old in Russia in 1950 be considered as old as a 60-year-old Swede in 2050? If not, is there a better alternative?”
The alternative proposed by Sanderson and Sharbov is to define the onset of “old age” as the point at which fifteen years of life expectancy remain. Through this lens, the past, present and future look very different.
In the United Kingdom, for example, which enjoyed strong increases in life expectancy until the last decade, the number of people over 65 increased by 8.3 million between 1981 and 2017, but the number of people under 15 year decreased. By 7.4 million. And if you are Recalculation Old-age dependency ratios, with this definition of “older people,” are lower in all regions of the world except sub-Saharan Africa and Oceania (excluding Australia and New Zealand), and are expected to rise less sharply.
Of course, this may not be the right lens either – that will depend on the specific issue you're concerned about. Ask questions about when people should be able to access their state pension. In recent years there has been a spread New “hours”. It aims to measure a person's “biological age” based on metrics such as proteins in the blood. Could it one day be used to set everyone's state retirement age, knowing that any system that uses chronological age or life expectancy is unfair to poorer people who live shorter lives?
Scott told me he's not sure people would accept that, even if clocks became scientifically robust enough. “Can you imagine two people of the same age, same job… but one is entitled (to his state pension) three years earlier?
There is no single ideal measure that can replace chronological age as a measure of population aging. But once you see the definition of “old” as something other than the number of years people have been alive, it starts to seem more malleable than deterministic, and those scary statistics about the pace at which we age seem more like a challenge. Of fate.
