Tsinghua and PKU undergraduates > grad students (in general, not necessarily). The problem is that most of the undergraduates go abroad for grad studies, so they get grad students mostly from 2nd tier schools. Now, China is large, and there are still a lot of good students for grad studies, but the best are already gone.

China is also EXTREMELY hierarchical. So, it is quite possible that a scholar (researcher, professor) with a very strong CV isn't doing much of the real work at all, instead it is pawned off to undergrad and grad students.

basically how US academia works. professors don't do the programming themselves. that's what graduate students are for.

No. Professors in the US generally spend lots of time managing their grad students and guiding their research, but not saying "here is my idea, go make it work;" they might help with writing papers and that is about it (also, I know many professors that still write their own code for their own ideas, and limit their advising student counts to do that).

In China, you'll often have one professor for around 50 students with three tiers (undergrads, masters/entry PhD/high-level PhDs). So not only is the professor not programming, but neither is the upper-level PhD student! Everything is just eventually being done by undergrads who will ship off to the states/west anyways.

On top of this many professors are often basically running sweatshops for their side businesses (since their university provided salary can be around 10K RMB/month).

OTOH the best students are more likely to be accepted internationally, and you're selecting from 19% of the world's population, so I'd expect the best to be very, very good. At that point it's almost like saying "the best students in half the Eastern hemisphere are very, very good."