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Lifespan depends on month of birth (2000)

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Re: Lifespan depends on month of birth (2000)

#31

Post by danielbarla »

EGreg wrote: post #26

It could also have something to do with their development in school. After all the school year is the same for all. Some kids are up to 11 months younger!

This is an area which I've personally experienced, having spent the first half of my school years in Europe, and being a few days shy of the cut-off point for being held back another year, I was always the youngest in my class (I guess on a large enough population, it would mean that similar kids are the smallest as well, on average).

Later on I switched to a southern-hemisphere school, which was out of phase by 6 months, and I was all of a sudden roughly average age in class. Not that it had a huge impact on me, but it was noticeable, which probably means it has some effect on average.

Re: Lifespan depends on month of birth (2000)

#33

Post by dmichulke »

I didn't fully read it but doesn't it look like there is potentially a big survivorship bias in the data?

They touch the subject with their 3rd hypothesis but in general it's possible that you still have a higher life expectancy being born from April-June in the Northern Hemisphere because you have increased chances of reaching 50.

So why this limit of 50 years? What is the expected lifespan for newborns depending on their month of birth?

Re: Lifespan depends on month of birth (2000)

#34

Post by CHY872 »

sillysaurus3 wrote: post #4
jcampbell1 wrote: post #3

This is interesting. They seem to think it is in utero effect. Maybe Vitamin D? I wondered if they considered if the cause is age when starting school. I know that birth month has pretty powerful effects for educational attainment.

What month should I conceive my child to maximize their educational attainment? I'm only half joking.

You want them to be born in September or October (or, more generally, a month or two after the school year starts). Probably October, so that there's no chance they're born in August. They'll be more developed than their July birthday brethren at every stage of their education - it's a very easy boost. For example, exams at 16 in the UK (GCSEs) that by and large everyone takes, you'd expect 54% of autumn birthday children to get 5 grades A*-C. You'd expect 48% of the summer birthday children to achieve this. At age 11, the gap is a slightly larger 8 points in terms of percentage of children who meet expectations.

This is a nontrivial difference, which makes it a trivial decision.

https://www.gov.uk/government/uploads/system/uploads/attachm...

Re: Lifespan depends on month of birth (2000)

#35

Post by awjr »

Would be interesting to look at the 'stresses' that occur within schools. My 11 year old daughter was born on the 30th of August. Ergo she is the youngest in the year at school. She is studying with people that have a year of development on her. She is doing fantastically well but works hard to achieve that result.

My hypothesis is that the age cut off in schools, unduly puts stress on the younger children in a class, that long term, impact on health in later years. In effect which month you are born in affects the stress you will feel during your school years as it will be inherently 'harder' for you.

Re: Lifespan depends on month of birth (2000)

#37

Post by jakobegger »

sillysaurus3 wrote: post #4
jcampbell1 wrote: post #3

This is interesting. They seem to think it is in utero effect. Maybe Vitamin D? I wondered if they considered if the cause is age when starting school. I know that birth month has pretty powerful effects for educational attainment.

What month should I conceive my child to maximize their educational attainment? I'm only half joking.

If school starts in september, around christmas.

Re: Lifespan depends on month of birth (2000)

#38

Post by beaumartinez »

awjr wrote: post #35

Would be interesting to look at the 'stresses' that occur within schools. My 11 year old daughter was born on the 30th of August. Ergo she is the youngest in the year at school. She is studying with people that have a year of development on her. She is doing fantastically well but works hard to achieve that result. My hypothesis is that the age cut off in schools, unduly puts stress on the younger children in a class…

I'd think the opposite. Since she is used to having to work hard from a young age, she will be more successful in life.

Others who coasted through—whom were used to everything being relatively easier—will not have the experience she has already accrued when faced with a harder challenge.

Re: Lifespan depends on month of birth (2000)

#39

Post by vertis »

peteretep wrote: post #27
sillysaurus3 wrote: post #4

Earlier quoted context omitted.

What month should I conceive my child to maximize their educational attainment? I'm only half joking.

> What month should I conceive my child to maximize their > educational attainment? I'm only half joking. I'm married to a primary school teacher. We are very definitely aiming to have babies born September to December. We aren't even slightly joking about that.

After that you just can't move somewhere that doesn't have the same timing on school years (e.g. Australia).

Re: Lifespan depends on month of birth (2000)

#40

Post by TorKlingberg »

EGreg wrote: post #26

It could also have something to do with their development in school. After all the school year is the same for all. Some kids are up to 11 months younger!

The effect of school could be isolated by comparing different countries with different cutoff dates. I believe the American and UK systems are based on age when the school year starts, so the youngest in the class were born in August. Sweden groups classes by birth year, so the youngest were born in December. The Japanese school year starts in spring.
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