It’s my birthday today and I have to admit that I woke up this morning thinking, “I’m 71 today and I wonder how much longer I have left.” That’s probably a little weird, but it got me to thinking about how to predict life expectancy.
Predicting how long you might live is not necessarily a morbid exercise. A relatively accurate prediction can be useful in a number of ways, including the very important retirement-planning task of estimating how much money you will need to live comfortably for the rest of your life.
Life expectancy at birth
But coming up with your life expectancy is not a simple or straightforward thing to do. The first misstep is to use the published numbers that show life expectancy at birth. For example, a boy baby born in the U.S. in 2017 is expected to live to age 76 and a girl baby to age 81 (the numbers vary by both gender and country of birth). This represents the average lifespan of people who were born in 2017 and who will die at any age thereafter, all based on current mortality rates.
These numbers are widely reported, often to show how life expectancies are rising in general across the whole world (they are) or dropping in the U.S. in the last couple of years (they are). But while they may be interesting for certain purposes, they are not the numbers to use to predict how long you, as a baby boomer, will live.
Even if you research the numbers from the year you were born, you will still not be on the right track. For example, in 1935 – the year Social Security was started – the life expectancy in the U.S. was 61. If you are reading this and you were born in 1935, you are now 82 or 83, so you can see how irrelevant that number is for your planning.
Life expectancy from the age we are now
What we need instead is a predictor of our life expectancy given the age we are now. We have already made it to a certain point – we baby boomers are now at least 54 years old, and we are in a different group from all of those who were born the same year we were – some number of them have already died. What we’re really looking for is an estimate of how many years we have left given how old we are now. The Social Security Administration (SSA) has just such a calculator at https://www.ssa.gov/oact/population/longevity.html.
But even that number is not a really good estimate. How many years we have left should be based not only on age and gender, but also on variables such as our current health, our lifestyles, our family histories, and so on. So a 75-year-old woman with diabetes and a hobby of parachute jumping will have a different life expectancy than a 75-year-old woman who goes to the gym three times a week and eats whole grains.
There are several online longevity calculators that take into account some of these additional factors. One, developed by the American Academy of Actuaries and the Society of Actuaries, is at http://www.longevityillustrator.org/. It takes smoking and health, in addition to gender and age, into consideration. A more complex calculator can be found at https://www.confused.com/life-insurance/life-expectancy-calculator, which includes factors such as whether you are happily married and how often you exercise.
It’s just a number
As curious as you may be to use these calculators, or to make predictions of your own using other methods, please remember that a prediction is not a fact. It’s just a rough estimate that can be useful to do some planning, but not to be seen as your destiny. Perhaps a better way is to follow the advice given two thousand years ago by the Roman Emperor Marcus Aurelius: “Perfection of character is this: to live each day as if it were your last, without frenzy, without apathy, without pretense.”
I'm Linda Fleit. My husband and I were lucky enough to retire when we were 61, about nine years ago. We love being retired and want to share all that we've learned over the years about this wonderful stage of life.