The data visualized here represents the distribution of scores from the PISA 2023 report, which can be found on the OECD website.
I mainly wanted to visualize the distribution of academic performance across and against different countries.

This is a single page HTML document; all the data and calculations are in the source, in case you want to fiddle with it locally. If you make any neat changes, send them over and I'll replace this page.

This is most definitely wrong, but of the few I checked the math lands about where I'd expect it to.
PISA scores are scaled to have an OECD average of 500 with a standard deviation of 100; likewise, if we assume 100 IQ with an SD of 15, we can [probably] use Z-Scores to translate one to the other.

Z = (X - PISA mean) / PISA SD

IQ = IQ Mean + (Z * IQ SD)

Where X is is the mean of the group in question. E.g., if we were to use Macao's mathematical score as an example:

Z = (552 - 500)/100

IQ = (100+(0.52*15)

107.8. Which is kind of where you'd expect metropolitan areas of Eastern China to land?

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Newly added Country IQ data (not the calculated estimate when using PISA scores) was taken from Emil Kirkegaard's "So you’re interested in the national IQ of a country, what do you do?"

If I've copied the PISA numbers wrong, or any of the math is retarded, give me a shout @thepenginsan.
It's also worth noting this report covers the Covid period (some noticeable drops in scores from prior years). The prior PISA report (covering 2018) was released in December of 2019.