Fourth- and eighth-grade students in the United States continue to lag behind students in several East Asian countries and some European nations in math and science, although American fourth graders are closer to the top performers in reading, according to test results released on Tuesday.

Fretting about how American schools compare with those in other countries has become a regular pastime in education circles. Results from two new reports, the Trends in International Mathematics and Science Study and the Progress in International Reading Literacy Study, are likely to fuel further debate.

South Korea and Singapore led the international rankings in math and fourth-grade science, while Singapore and Taiwan had the top-performing students in eighth-grade science. The United States ranked 11th in fourth-grade math, 9th in eighth-grade math, 7th in fourth-grade science and 10th in eighth-grade science.

Although the average scores among American students were not significantly lower than the top performers, several nations far outstripped the United States in the proportion of students who scored at the highest levels on the math and science tests.