of saying non-original things.
Using the shanghaied students in the PISA tests as your “sample” is about as representative as using any major American big city’s public school students. And that’s assuming no fishiness with things on the red side, which is not something regular Chinese people would even think to consider.
It would be somewhat like taking Gansu (no offense Gansu, you great Arkansas of the East) high school students (the ones who go to school, and therefore have schools) and putting them up against the elite private schools on the east coast. And those elite private school kids were drilled their whole life with a testing culture, and told if they did bad it would shame the country and their family (and they would have to care about those things), and were not allowed to have lives, and studied all day, and learned essentially the things that would be on the test, and then you selected the most capable of those as your sample.
I’m not making any apologies about American schools, I went to them. The problem isn’t always the schools. Most of the kids at the schools are dumb. We try to educate everybody and fail to educate many of them successfully, not always due to the fault of the school. It’s like comparing apples to oranges, mandarin oranges, which I think are just 橘子.
The things you don’t know about the Chinese school system could fill a map of the world, life-size.