Results for the latest administration of the Program for International Student Assessment, a key exam given to 15-year-old students worldwide, show poor performance in reading and math among U.S. students, with the Common Core national standards and aligned curriculum a likely significant contributing factor.

The PISA exam tests reading, math, and science. Among the 79 countries where the exam is administered, the top scorers were students in four provinces in China — Beijing, Shanghai, Jiangsu, and Zheijiang.