To zoom out a bit, I don’t think this post even asks the right question. Why does quantity of STEM major matter, as opposed to quality? The USA is home to the vast majority of leading universities, and no amount of PISA score dominance by Chinese children can change that. If anything, China should be worried about the continuous brain drain of their best, brightest, and most of all wealthiest to Canada and the USA. Not to take anything away from the hard work and ambition of those Chinese people who wish to stay in China, but I just don’t agree that this difference in test scores taken by public high school students is any sort of leading indicator of shifting geopolitical trends.