TIL: B-S-J-Z (China) in the rankings means Beijing, Shanghai, Jiangsu, and Zhejiang. Instead of testing mainland China as a whole, the OECD allows these four specific provincial-level jurisdictions to represent China in the triennial PISA rankings for 15-year-old students.
Why is China constantly allowed special treatment like this? I bet if the US only submitted scores from select wealthy Massachusetts and NoVA counties you’d see some crazy numbers.
Eitherway, hard to say, but look at proxy indicators, there's fuckload of "dumb" Chinese international students... i.e. those who couldn't hack GaoKao that are basically A students in western tertiary. And as others have mentioned, BSJZ + kids that pass zhongkao is basically more 2+ standard deviation talent pipeline than OCED combined, disproportionately directed at technical tertiary, i.e if you want to know who has most big brains whose going to be doing the cooking in the future, BSJZ is good indcator.