[IronJack]

I don't think that's the way life expectancy is calculated. It's more a measure of how many died young. If a lot of people died in infancy, for example, it would lower the life expectancy. But that doesn't mean that the average person only lived 12 years; it just means that if you averaged out the lifespans of every person born, it would come out to be about 12 years.

It's a common misconception.

[patton]

“But that doesn’t mean that the average person only lived 12 years; it just means that if you averaged out the lifespans of every person born, it would come out to be about 12 years.”

Care to think that one through again?

I understand what you are trying to say - that some died minutes after birth, and others lived to the ripe old age of 30, so it averages to 16.

But what you said is not what you think you said.

[Vermont Lt]

I always got into that argument with the lifespan of our customers (not their real life, but the time they were customers.) Some measured it in terms of how long “dead” customers had been with us. I always measured the average time that a current customer had been with us.

I always think the proper metric is something like a median lifespan—where half the people live longer, and half die earlier.