[bumby]

Not to make a nitpick in your point because it's a good one, but it made me wonder:

How different would the height measure be if it were standardized like IQ? E.g., how likely would someone who is in the 90% percentile in 6th grade be in the 90% percentile as an adult? From that perspective, I imagine the standardized height "re-test" correlation is a lot less than 1.0 (although it would certainly be close to that with two measures of height as an adult).

[dmurray]

0.8 correlation with adult height for boys aged 4, according to [0]. The real study [1] is paywalled but looks legit. I'm guessing it's even higher at age 12, though it might be confounded by puberty soon after.

[0] https://www.theatlantic.com/ideas/archive/2020/02/can-you-pr...

[1] https://pubmed.ncbi.nlm.nih.gov/21767107/