U.S. teens are far behind their Chinese counterparts in an exam taken by students around the world, The Wall Street Journal reports. The test, called the Program for International Student Assessment, or PISA, is given to a representative sample of about 600,000 students in 79 countries and education systems every three years. U.S. students showed an average reading score of 505 out of 1,000, a math score of 478, and a science score of 502, trailing behind Chinese students in each subject. China had the highest scores of all nations in all three subjects, topping perennial leader Singapore with an average reading score at 555, math at 591, and science at 590. “The scores are flat. We’re struggling in math in comparison to our peers around the world,” said Peggy Carr, the associate commissioner of assessments for the National Center for Education Statistics. “We’re sliding with regard to our most struggling readers.” The results also show a widening gap between higher- and lower-performing students in the U.S. in reading and math.