While there is less income inequality in Estonia than in the United States—and, with 1.3 million people, the country is significantly smaller—the Baltic nation also has its share of cultural diversity. When it achieved independence from the Soviet Union 25 years ago, Estonian became the official language and the language of school instruction. Yet about a fifth of its students come from families that still speak Russian at home, and they have historically lagged behind their native speaking counterparts on tests such as PISA.

Though its students may come from diverse backgrounds, Estonia’s schools give them very similar educational experiences. In embracing students of all backgrounds and income levels, Estonia has succeeded not only on exams but on a goal that many policymakers, educators, and advocates say the United States must achieve: creating an educational system based on equity. The idea is a holdover from the Soviet era and one that the country intends to keep even as it continues to grapple with how to modernize its schools and further shrink the already small achievement gaps among its students.

As a result of this commitment, Estonia’s performance on PISA isn’t in spite of its poor students; it’s in no small part because of them.

“We have been able to keep education very even,” said Jürgen Ligi, the Estonian minister of education. “It has worked.”

On the 2012 PISA math exam, more than a third of low-income students were among the country’s top performers. Estonia had the second smallest gap in performance between its poorest and richest students out of all participating countries known as the Organization for Economic Cooperation and Development (OECD). Students in its lowest income quartile scored about as well as American students in the second highest income quartile.

Marc Tucker, president of National Center on Education and the Economy in Washington, D.C., visited Estonia last year to find out what they’re doing right. He said that after the fall of the Iron Curtain other former Soviet satellites, such as Hungary and the Czech Republic, transitioned to a system preferentially suited to the needs of its elites. Estonia, however, kept giving equal opportunities to students of all backgrounds.

“What [we] saw in Estonia was not a new education system, it was an old one,” Tucker said. “By every account they did not change the system after the wall came down…. It’s hardly surprising they continued to get great results.”

There are many factors that may contribute to Estonia’s success on PISA beyond their focus on equality. Education continues to be highly valued. Teacher autonomy is relatively high, which has been shown to be related to better test scores. Teachers stay with the same students in grades one to three – or sometimes even up to sixth grade - allowing deep relationships to develop. Many officials and educators say teachers here are good at supporting students and preventing them from getting off track, in contrast to the U.S., where teachers spend a lot of time intervening to help students who have fallen behind.