# Are you young, middle-aged or old? You may be pleasantly surprised

That’s not a serious question in the title, right? It’s not as if there’s any clear delineation between those age categories – you aren’t young one day and middle-aged the next, for example. But still, when we read novels written a long time ago and someone is called middle-aged, we have a pretty good impression in our minds about what that person is like.

And we probably still carry in our minds those old-fashioned ideas about what ages fit into which range. For example, the authors of an academic paper in the early 2000s about gambling chose to classify their subjects as young adults (aged 18-35), middle-aged adults (36-55) and older adults (older than 55). Gosh, what old-fashioned ranges, and how insulting to us all!

Skip to the end if you’re impatient to see what ages today are the true modern equivalents of being young, middle-aged and old. Then come back and indulge me as I explain it all.

Okay, so you didn’t expect this to be about actuarial calculations. But it is. It has to do with mortality tables. Here’s the gist of how those tables are constructed.

## Adding it up

At the start of every year, divide the population into sex and age groups: females 20, females 21, females 22, males 20, males 21, males 22, and so on. Count how many there are in each group. Check how many in each group pass away in that year. And calculate the survival rate (like 999 out of 1000, and so on). Well, you don’t have to do that yourself, of course, but it’s the most fundamental actuarial calculation. (Traditionally actuaries calculate what they call the mortality rate, like 1 out of 1000 in this example, but it’s far more cheerful to think of longevity rather than mortality.)

If you do that for every age and each sex, you have what’s called a ‘life table’. From that ,you can (if you’re an actuary) calculate how many years are lived by a particular group whose lives follow that table.

For example, a group of 1000 males aged 20 (in my made-up example) lived 999 years (since one died) in that year of being age 20; those 999 survivors might live 998 years in total as 21-year-olds, and so on, to the end of the table (which typically goes to age 110 or 120).

Suppose, by the end of the table, if they follow the mortality/longevity rates for each age, they’re projected to live a total of 65,000 years. Then, since there were originally 1000 of them, it means that (on average) they’ll live 65 more years. Of course, that’s an average (65,000 divided by 1000) – one poor fellow, in this example, doesn’t even live one more year (the one who passes away before reaching age 21), and there’s probably one who is projected to reach 110 – but on average, 65 more years.

## Understanding life expectancy

That’s called the ‘life expectancy’ – and it’s a very much misunderstood term. There’s nothing ‘expected’ about it, even though that’s what many people often understand it to mean, ‘I’m expected to live to 85, but not beyond.’ I much prefer calling it something like ‘average future survival years’ – but never mind, that’s just my rant.

Okay, so what has all of this got to do with your stage of life?

Well, in the olden days … people used to be thought of as young until their mortality rate reached roughly 1 per cent, and middle-aged until their mortality rate reached roughly 4 per cent. At any rate, that’s what my friend Dr John Shoven told me – and, among many distinctions, he was the Trione Director of the Stanford Institute for Economic Policy Research and the Charles R. Schwab Professor of Economics at Stanford University.

The US Social Security Administration has compiled and published life tables since 1900, so I looked up the ones for 1900. Male mortality rates reached 1 per cent at age 37, and 4 per cent at age 65. Well, that’s reasonably close to what those academics studying gambling used.

The thing is, though, that mortality rates at each age have been falling – quite a lot – since then, meaning that longevity has been increasing.

How much? Well, I looked up the 2010 tables. One per cent  was reached at male age 60 and female age 64, and 4 per cent was reached at male age 75 and female age 78. At which point, incidentally, the average future survival years were roughly 20 and 10 years. Aha, I think that’s a lot more understandable than mortality rates of 1 per cent and 4 per cent. So let’s take those average future survival years as the interpretation of John’s rule.

## The big conclusion

So, here’s the big conclusion.

Today, you should consider yourself young until your average future survival years are 20 (male 60, female 64), and then middle-aged until your average future survival years are 10 (male 75, female 78). Those male ages are easy to remember, ending in 0 or 5. The female ones feel a bit random. So, if it helps, round up the female ages slightly and remember them as 65 and 80: in both cases, five years higher than the male ages.

Another convenient way to use the 20-year and 10-year translations is that, if you’re in a country other than the US, check that country’s life tables to see at what ages the average future survival years are 20 and 10. And then, those are the approximate transition ages from youth into middle-age, and from middle-age into old(er) age.

Yes, I know these are only averages, and that they take into account only your chronological age (how many years old you are), not your biological age (that is, the age corresponding to how your body actually behaves) – so they may not apply to you in particular. (Professor Moshe Milevsky reminded me once that the only thing that your chronological age measures accurately is how many times you’ve been around the sun!)

But you should surely be encouraged by how very different these ages are from what we’ve been brought up to consider as young, middle-aged and old. And you can undoubtedly consider yourself much more youthful, on this scale, than you thought. That’s great news!

If you know any actuaries, say ‘thank you’ to them.

You’re welcome!

## Takeaway

Consider yourself young until you reach age 60 (male) or 65 (female), then middle-aged until age 75 (male) or 80 (female). See, you’re much more youthful than you thought!

Also read: Retirement, ‘discretionary hours’ and purpose

Don Ezra is an author, a former actuary and US-based retirement blogger. This article originally appeared on Don Ezra’s website.