5th and 6th-grade students warm up for class at For Academy for Ideal Education, a private school that serves students in grades Pre-Kindergarten and K-12. (Astrid Riecken/FOR THE WASHINGTON POST)

D.C. students who use vouchers to attend private schools perform significantly worse in math than their public school peers, according to a federal study that could cast a cloud over Education Secretary Betsy DeVos’s quest to expand voucher programs across the country.

The District is home to the nation’s only federally funded voucher program and its experience provides fodder to advocates on both sides of the national debate.

This week’s study from the Institute of Education Sciences, part of the U.S. Education Department, found that math scores were 10 percentage points lower for students who used vouchers compared with students who applied for the scholarship program but were not selected through a lottery. The students who were not chosen for the voucher program typically attend public schools in low-income neighborhoods.

Reading scores for voucher students were also lower, though the difference was not statistically significant.

Matthew Chingos, director of the Urban Institute’s Education Policy Program, said the findings of the study could be used to guide officials who seek to boost students’ academic performance. He stressed that test scores are just one measure of student achievement.

“My question for policymakers is, how do we use public support to provide families access to good schools?” Chingos said. “If we see kids who are using choice to go to a certain school and they aren’t benefiting from them, then we should think about what policy design will help them benefit from them.”

The federal study assessed children two years after they applied to use vouchers.

The Department of Education did not immediately return a request for comment.

In the past, specialists have said weaker scores among voucher recipients may say as much about improvements in traditional public schools as they do about private schools.

DeVos, who was an education activist before being tapped as the nation’s top education official, is an ardent voucher proponent and has donated millions of dollars to candidates who share her fervor for vouchers. She has said she believes that vouchers enable low-income families to escape their low-performing neighborhood schools.

Vouchers, deeply controversial among supporters of public education, are direct government subsidies parents can use as scholarships for private schools. These payments can cover all or part of the annual tuition bills, depending on the school.

A 2017 Department of Education study found that D.C. voucher students performed worse on standardized tests within a year after entering private schools than peers who did not participate.

Eleanor Holmes Norton (D), the District’s nonvoting delegate to Congress and a fierce opponent of vouchers, said the new study shows the program is ineffective.

“That is my chief regret about the voucher program,” Norton said. “If Congress is interested in putting money in schools, it should be putting that money where the results show the money should be.”

Congress established D.C.’s voucher program — known as the District of Columbia Opportunity Scholarship Program — in 2004. The program, which serves about 1,100 students, prioritizes students from low-income families trying to leave low-performing schools. Vouchers provide each student about $8,000 to attend an elementary or middle school, and $12,000 for high school.

The congressional act that set up the program required that the federal government examine the effectiveness of the plan two years after eligible students apply. In addition to examining test scores, the IES report looked at student and parent satisfaction at schools.

The report, which was released this week, found that parents who used the vouchers were more likely to perceive their schools as “very safe.” There was no statistically significant difference in parents’ general satisfaction regarding schools.

Students who did not receive vouchers and are included in the study do not necessarily attend their neighborhood schools.

A 2012 investigation by The Washington Post found that more than half of voucher recipients attended Catholic schools, and many went to schools where almost all students were voucher recipients.

A 2010 report from the Education Department that examined the D.C. program found that graduation rates were higher among voucher recipients than public school students, according to results submitted from parents. But no evidence existed that vouchers were tied to improved student achievement.