I’m sure this has been done before, but combinations fo search terms failed to turn up what I’m looking for.
Anyway, I was born in the USofA in 1970. Life expectancy for an American male in 1970 was, say 73.1 years (I’m just making up a number here; someone with better google skills can look up the exact number). Life expectancy for an American male in 2005 is, say 77.6 years (again, just making up a number).
So what is my life expectancy? The figure of my birth, or the current figure?
Current. A lot of the number is based on lifestyle and medical advancement.
Check this out…
http://moneycentral.msn.com/investor/calcs/n_expect/main.asp
Most likely neither. Your life expectancy changes as you age. You have, for example, survived the teenage driver phase that causes a small but measurable spike in mortality from about 16 to 25. If you reach the age of 80, you can be sure that your life expectancy is greater than 77.6.
The simplest way to measure your life expectancy would be to look at history and measure how long males of your age have tended to last, on average.
This could be refined by considering your exposure to know risks: Are you a smoker? Smokers don’t tend to last as long as do non-smokers of the same age. Other risk exposures might include high blood pressure, obesity, family history of serious diseases, participation in risky activities, etc.
There’s also the point that medical advances can reduce the extent to which certain diseases shorten peoples lives. This is one explanation for life expectancy being longer today than when you were born. Even though they weren’t around when your original life expectancy was estimated, you get then benefit of them if needed.
Actually I think most life expectency tables are from age 1 year so as to leave out the infant mortality. Life expectancy at 1 year is just that, average age at death for someone who is one year old now.
If you reach age 20 there is a new life expectancy which is the average age at death for someone who is now 20 years old.
Say life expectency at 1 year was 73 years as you postulate. Half the people will die before 73 and half after. If you are in the surviving half when you are 73 you get a new life expectency which might be, say 12 years. OK, at 85 you are in the half that still lives, you now get a new life expectency, maybe 4 years. At 89 you’re still here so you get another reprieve, and so on.
As people have said, that figure is an average for all males.
For you, it will vary depending on your individual decisions on things like smoking, drinking, exercise, etc. And it will vary depending on your genetics – how long did your father & grandfathers live?
Google on “life expectancy quiz” and you can find lots of free online quizs where you answer questions about these things, and they will give you an estimated life expectancy. This is still an average, but one based on people like you, so likely to be closer to you individually.
Here’s a couple of sites:
http://www.agingresearch.org/calculator/quiz.cfm
http://moneycentral.msn.com/investor/calcs/n_expect/main.asp
It might be interesting to try this at several sites, and see how close their answers are.
Most tables that I have seen start at age 0, thus giving life expectancy at birth. Here’s an example from the Australian Government Actuary’s office: PDF file.