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Aren't life expectancy at birth figures heavily skewed by infant mortality rates. I think this is quite a commonly misunderstood statistic for this reason. So w

Aren't life expectancy at birth figures heavily skewed by infant mortality rates. I think this is quite a commonly misunderstood statistic for this reason. So while it's true that in the past a new born baby's chances of becoming a great grandparent were much lower than they would be today, that would mainly be due to the low chances of them ever reaching adulthood and becoming a parent at all, rather than the chances of parents living beyond 47.

gampleman 3y ago
Exactly. While life expectancy from adulthood (say 20 yo) has increased (i.e. UK males have gone from expected average 60y to 80y between 1841 to 2011 [1]), it hasn't increased nearly as much as the life expectancy from birth (i.e. 33% vs 98% increase over that period). [1]: https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/lifeexpectancies/articles/howhaslifeexpectancychangedovertime/2015-09-09 https://www.ons.gov.uk/peoplepopulationandcommunity/birthsde...
- levocardia 3y ago
  The increase for a 40 year old is still nearly 14 years of extra life, though. That's a big difference.
jncfhnb 3y ago
Pretty sure the probability of making it to adulthood has never been below 50% excluding war, plague, or famine (which were common, so hard to normalize)
- deleted 3y ago
  [deleted]
- ako 3y ago
  Wikipedia seems to suggest you might be wrong: https://en.wikipedia.org/wiki/Life_expectancy#Variation_over_time https://en.wikipedia.org/wiki/Life_expectancy#Variation_over... For example, for Ancient Rome it says “ while the ~50% reaching age 10 could expect another 40 years of life”.
  - jncfhnb 3y ago
    Hmm I’m surprised. But if 50% reaches an average age of, say 2, assuming it’s right skewed for those who died before 10; then an average life expectancy of 50 for the remainder means the average life expectancy overall just 26. That squares with the numbers stated I suppose.
gmane 3y ago
I thought this as well, but I did a little research before responding, and it looks like even though this is broadly true, people still weren't living particularly long before the modern era. For example, in Ancient Greece, a man who lived to 15 would expect to live to 37-41 years, in Rome if a man made it to 20 they could expect to live to 60, in the late medieval if you made it to 25 you could expect to live to ~48 [0]. You still need to make it to 60 to be a great grandparent, assuming you and your kids are having kids at ~15 years of age (edit: and that might be a friendly assumption given how high infant mortality was). [0] https://en.wikipedia.org/wiki/Life_expectancy https://en.wikipedia.org/wiki/Life_expectancy
- alex_young 3y ago
  There's some uncertainty about this, and while not properly controlled for obvious reasons, a study of lives of men of renown in 5th and 4th century Greece found a median life expectancy of around 70: https://pubmed.ncbi.nlm.nih.gov/18359748/ https://pubmed.ncbi.nlm.nih.gov/18359748/
keybored 3y ago
This is such a rookie mistake to make (by the author). Can’t believe that people who write about this topic still don’t know this in this day and age.
timeon 3y ago
I think it was not just infants but young kids as well but yeah.
- bregma 3y ago
  "Infant mortality" refers to the mortality rate for those under 10 years of age.
tgv 3y ago
Not only. Check the mortality rates. They've gone down for the higher ages. People really live longer past childhood.

gampleman 3y ago

Exactly. While life expectancy from adulthood (say 20 yo) has increased (i.e. UK males have gone from expected average 60y to 80y between 1841 to 2011 [1]), it hasn't increased nearly as much as the life expectancy from birth (i.e. 33% vs 98% increase over that period). [1]: https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/lifeexpectancies/articles/howhaslifeexpectancychangedovertime/2015-09-09 https://www.ons.gov.uk/peoplepopulationandcommunity/birthsde...

levocardia 3y ago
The increase for a 40 year old is still nearly 14 years of extra life, though. That's a big difference.

jncfhnb 3y ago

Pretty sure the probability of making it to adulthood has never been below 50% excluding war, plague, or famine (which were common, so hard to normalize)

deleted 3y ago
[deleted]
ako 3y ago
Wikipedia seems to suggest you might be wrong: https://en.wikipedia.org/wiki/Life_expectancy#Variation_over_time https://en.wikipedia.org/wiki/Life_expectancy#Variation_over... For example, for Ancient Rome it says “ while the ~50% reaching age 10 could expect another 40 years of life”.
- jncfhnb 3y ago
  Hmm I’m surprised. But if 50% reaches an average age of, say 2, assuming it’s right skewed for those who died before 10; then an average life expectancy of 50 for the remainder means the average life expectancy overall just 26. That squares with the numbers stated I suppose.

gmane 3y ago

I thought this as well, but I did a little research before responding, and it looks like even though this is broadly true, people still weren't living particularly long before the modern era. For example, in Ancient Greece, a man who lived to 15 would expect to live to 37-41 years, in Rome if a man made it to 20 they could expect to live to 60, in the late medieval if you made it to 25 you could expect to live to ~48 [0]. You still need to make it to 60 to be a great grandparent, assuming you and your kids are having kids at ~15 years of age (edit: and that might be a friendly assumption given how high infant mortality was). [0] https://en.wikipedia.org/wiki/Life_expectancy https://en.wikipedia.org/wiki/Life_expectancy

alex_young 3y ago
There's some uncertainty about this, and while not properly controlled for obvious reasons, a study of lives of men of renown in 5th and 4th century Greece found a median life expectancy of around 70: https://pubmed.ncbi.nlm.nih.gov/18359748/ https://pubmed.ncbi.nlm.nih.gov/18359748/

keybored 3y ago

This is such a rookie mistake to make (by the author). Can’t believe that people who write about this topic still don’t know this in this day and age.

timeon 3y ago

I think it was not just infants but young kids as well but yeah.

bregma 3y ago
"Infant mortality" refers to the mortality rate for those under 10 years of age.

tgv 3y ago

Not only. Check the mortality rates. They've gone down for the higher ages. People really live longer past childhood.