U.S. TEENAGERS underperformed in math, reading and science when compared with many of their peers around the world. That was the disappointing news from the latest round of international assessments. But the assessments also showed progress in improving equity and closing the achievement gap, an encouraging sign that some efforts to strengthen schools are on the right track.

Results released this month from the 2015 Program for International Student Assessment (PISA), administered every three years to evaluate education systems worldwide by testing the skills and knowledge of 15-year-olds in some 70 countries, showed the U.S. system in the middle of the pack in reading and science and near the bottom on math. The reading and science test scores were on par with U.S. performance in 2012, while the math results dipped slightly. A singular bright spot was a narrowing of the achievement gap between rich and poor students. No other country, said Andreas Schleicher, who oversees the test at the Organization for Economic Cooperation and Development, is making greater progress on closing its equity gap.

Could that be the result of the closer attention that states and districts were required to pay to minority and other at-risk children under the wrongly maligned and forsaken federal No Child Left Behind Act? Experts rightly caution against trying to draw a straight line from policy to standardized test scores, but PISA has proven to be useful with its nuanced insights into what seems to work and what seems not to. For example, a common trait among countries that consistently score high on these assessments is their insistence on high academic standards that encourage conceptual thinking and understanding. Only of late did the United States move toward such high standards, as many states adopted the Common Core. It is important to stick with those standards and give them the opportunity to have an effect rather than, as has become politically fashionable, demonize them.

Other lessons emerge: the effectiveness of high-quality preschools, attention to attendance, devoting more and better resources to the neediest students, and having a professional teaching force. PISA, like all tests, has its flaws, but no number of excuses about the different social structures or student demographics of other countries can sugarcoat the shortcomings in American education — or the difficulties the country faces if its workforce can’t compete against its foreign counterparts.