Indeed, some countries, including China, abuse the sampling mechanism. See "Are The PISA Education Results Rigged?", https://www.forbes.com/sites/realspin/2017/

Indeed, some countries, including China, abuse the sampling mechanism. See "Are The PISA Education Results Rigged?", https://www.forbes.com/sites/realspin/2017/01/04/are-the-pisa-education-results-rigged https://www.forbes.com/sites/realspin/2017/01/04/are-the-pis... Among all OECD countries the U.S. scores slightly above average in all three categories (even accounting for score inflation), though math and science scores could arguably use some improvement: See https://www.oecd.org/pisa/PISA-results_ENGLISH.png https://www.oecd.org/pisa/PISA-results_ENGLISH.png