Comments on: All the twin pairs came in for physical examinations, and the results were pretty much what you’d expect https://www.isegoria.net/2022/12/all-the-twin-pairs-came-in-for-physical-examinations-and-the-results-were-pretty-much-what-youd-expect/ From the ancient Greek for equality in freedom of speech; an eclectic mix of thoughts, large and small Wed, 27 May 2026 12:30:29 +0000 hourly 1 http://wordpress.org/?v=3.6.1 By: Jim https://www.isegoria.net/2022/12/all-the-twin-pairs-came-in-for-physical-examinations-and-the-results-were-pretty-much-what-youd-expect/comment-page-1/#comment-3580429 Jim Sat, 24 Dec 2022 20:46:06 +0000 https://www.isegoria.net/?p=49509#comment-3580429 Gwern is truly a national treasure.

]]> By: Gavin Longmuir https://www.isegoria.net/2022/12/all-the-twin-pairs-came-in-for-physical-examinations-and-the-results-were-pretty-much-what-youd-expect/comment-page-1/#comment-3578644 Gavin Longmuir Wed, 21 Dec 2022 20:18:09 +0000 https://www.isegoria.net/?p=49509#comment-3578644 Isegoria wrote: “according to Wikipedia”

Wikipedia? Let’s be serious!

]]> By: Gwern https://www.isegoria.net/2022/12/all-the-twin-pairs-came-in-for-physical-examinations-and-the-results-were-pretty-much-what-youd-expect/comment-page-1/#comment-3578641 Gwern Wed, 21 Dec 2022 18:36:13 +0000 https://www.isegoria.net/?p=49509#comment-3578641 Scandinavian countries like Finland usually have a proper population register, so it is easy to find all the twins (fraternal or identical) and collect data. You don’t need to call them back in for stuff like income or medical records because you just look them up using the register, you get IQ and personality and some other things for the men from the draft examinations, and so on. That’s why they do such amazing public health and economic research. Their real limit is simply that they are so small, so for rare things like twinning, the sample size can still wind up unfortunately small (adequate for normal analyses like heritability of exercise behavior or BMI, but then when you look for discordant twin pairs specifically, you may be underpowered). You can accumulate cohorts over time, but of course that causes problems of its own if you aren’t interested in the temporal trends.

]]> By: Jim https://www.isegoria.net/2022/12/all-the-twin-pairs-came-in-for-physical-examinations-and-the-results-were-pretty-much-what-youd-expect/comment-page-1/#comment-3578640 Jim Wed, 21 Dec 2022 18:25:49 +0000 https://www.isegoria.net/?p=49509#comment-3578640 Very interesting.

]]> By: Isegoria https://www.isegoria.net/2022/12/all-the-twin-pairs-came-in-for-physical-examinations-and-the-results-were-pretty-much-what-youd-expect/comment-page-1/#comment-3578634 Isegoria Wed, 21 Dec 2022 15:41:02 +0000 https://www.isegoria.net/?p=49509#comment-3578634 “Monozygotic twinning occurs in birthing at a rate of about 3 in every 1000 deliveries worldwide (about 0.3% of the world population),” according to Wikipedia, so millions of Finns should yield thousands of twins.

]]> By: Gavin Longmuir https://www.isegoria.net/2022/12/all-the-twin-pairs-came-in-for-physical-examinations-and-the-results-were-pretty-much-what-youd-expect/comment-page-1/#comment-3578633 Gavin Longmuir Wed, 21 Dec 2022 15:22:51 +0000 https://www.isegoria.net/?p=49509#comment-3578633 “The twins in the study were drawn from two previous Finnish twin studies that included thousands of pairs of identical twins.”

Population of Finland is only about 5.5 Million people. Considering how seldom one comes across identical twins in daily life outside Finland, the rational observer has to say — What?

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