Context: The OECD PISA score is a bullshit number that takes raw scores (which they don't publish, but there have been leaks) and curve them based on factors that have nothing to do with actual student performance on the tests, like "does your country have universal healthcare". Also, while every US student is subject to inclusion for our testing, other countries exclude low performers. China famously excludes most of their population, and only includes students at state schools in the four wealthy provinces, which is why you sometimes see China annotated as "B-S-J-Z". European nations are like Norway, Sweden, the Netherlands, and Spain get to exclude vast swaths of their students from testing, which moves the score 10 to 15 points.