On average, 13 percent of students scored at the highest or second highest level on the PISA test, making them “top performers.” Fifty-five percent of students in Shanghai-China were considered top performers, while only nine percent of American students were.

One in four U.S. students did not reach the PISA baseline level 2 of mathematics proficiency. At this level, “students begin to demonstrate the skills that will enable them to participate effectively and productively in life,” according to the PISA report.

Even the top students in the United States are behind: This year, the PISA report offered regional scores for Massachusetts, Connecticut, and Florida. Massachusetts, which is a high-achieving U.S. state and which averaged above the national PISA score, is still two years of formal schooling behind Shanghai.

America Spends a Lot of Money Per Student

The U.S. ranks fifth in spending per student. Only Austria, Luxembourg, Norway, and Switzerland spend more per student. To put this in context: the Slovak Republic, which scores similarly to the U.S., spends $53,000 per student. The U.S. spends $115,000. The PISA report notes that, among OECD countries, “higher expenditure on education is not highly predictive of better mathematics scores in PISA.”

Socio-Economic Class Plays a Larger Role in the U.S. Than in Other Countries

Fifteen percent of the American score variation is explained by socio-economic differences between students. Less than 10 percent of score variation in Finland, Hong Kong, Japan, and Norway is due to socio-economic differences.

The U.S. also has a lower than average number of “resilient students,” which PISA defines as “students who are among the 25 percent most socio-economically disadvantaged students but perform much better than would be predicted by their socio-economic class.” On average, seven percent of students are considered resilient. Thirteen percent of of students in Korea, Hong Kong, Macao-China, Shanghai-China, Singapore, and Vietnam are “resilient.”

The Countries That Are Doing Well

Parts of China, Singapore, Japan, Korea, and Liechtenstein topped the rankings for math, reading, and science. Finland, which is often pointed to as an example of an excellent school system, continued to perform well. However, the country dropped 2.8 points in math, 1.7 points in reading, and three points in science in “annualized changes in score points,” which are the “average annual change in PISA score points since the country’s earliest participation in PISA.”

The biggest annualized score improvements came from Brazil, Tunisia, Mexico, Turkey, and Portugal. Italy, Poland, and Germany also showed gains since 2003.

Click for larger image of chart

How seriously should we take these dismal findings? Educators around the world have called for tempered reactions to the PISA scores and questioned the usefulness of the tests. Nevertheless, this year’s report—and the United States’ poor math results—may be worth paying attention to for at least one reason. A 2011 study found that PISA scores are an economic indicator: rising scores are a good sign that a country’s economy will grow as well.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.