Third-graders at Arlington’s Carlin Springs Elementary School work on a math lesson in September 2014. Carlin Springs Elementary is one of 136 schools statewide that is considered highly segregated. (Amanda Voisard/For the Washington Post)

Virginia’s schools have grown more racially and economically segregated during the past decade, with the number of students attending schools that are considered racially and economically isolated doubling from 2003 to 2014, according to a new report.

The number of Virginia schools isolated by race and poverty has grown from 82 in 2003 to 136 in 2014, according to the Commonwealth Institute, a left-leaning think tank based in Richmond. The number of students in those schools has grown from about 36,000 to more than 74,000, according to the report, published this month.

The report defined an isolated school as one where more than 75 percent of the students are black or Hispanic and more than 75 percent of students qualify for free or reduced-price meals, an indicator of poverty.

The report offers more evidence that the nation’s public schools are resegregating. In May, the Government Accountability Office reported that the number of public schools serving primarily poor black and brown students had doubled nationwide.

The Commonwealth Institute did not examine outcomes for students in isolated schools in Virginia, but the GAO report found that isolated schools were less likely to offer a full range of math and science courses than other schools, for example, and were more likely to use expulsion and suspension as disciplinary tools. Such schools also have difficulty attracting and retaining teachers, and poor students fare better when they attend school with more affluent peers, according to the report.

“The peer effects have been shown to have really big impacts on their ability to have good outcomes,” said Chris Duncombe, a Commonwealth Institute policy analyst and one of the report’s authors.

Richmond Public Schools, where about 75 percent of the student body is black and nearly every child qualifies for free or reduced-price meals, had the highest number of isolated schools in Virginia, with 29.

But researchers also found isolated schools in affluent Northern Virginia districts. In 2014, Prince William County had 11 such schools, Fairfax County had five, and Arlington had two.

“Prince William County is the 12th wealthiest county in the entire country and yet you have 11 schools within that school division that have that powerfully negative combination of high poverty and high minority students,” said Michael Cassidy, president and chief executive of the Commonwealth Institute.

Prince William’s school system works to alleviate the challenges poor students face by sending extra teachers to high-needs schools and providing additional professional development for teachers in these schools, said spokesman Phil Kavits. And he said some of those efforts have been getting results: West Gate Elementary, considered an isolated school, had one of the county’s highest pass rates for mathematics.

Kavits said that the district considers demographics when it draws enrollment boundaries, but it is difficult to create demographically balanced schools as the number of minority students grows. Hispanic students this year surpassed the number of white students in the district, the second-largest in Virginia.

“The report reflects the clear challenges that remain in establishing school boundaries in such a diverse area as Prince William County,” Kavits said.

Alexandria, where more than half of the city’s public school students qualify for free or reduced-price meals, had five schools that fell into the isolated category. After seeing rapid growth in its immigrant population, the city is redrawing enrollment boundaries and taking demographics into consideration. Like other school districts, Alexandria sends extra resources — some drawn from federal sources — to its neediest schools, allowing schools to boost their supplies, hire extra staff and give intensive help to high-needs children.

Ingrid Bynum, principal of Patrick Henry Elementary — where more than 80 percent of students are black or Hispanic and more than 80 percent of students qualify for free and reduced-price meals — said educating students in poverty means meeting basic needs first, such as ensuring children have shoes and underwear and enough to eat at home.

“With our free- and reduced-meal population being so large, we are having to compensate or take away the barriers that affect children,” Bynum said.

The school’s test scores have soared under Bynum, and its students, despite their challenges, have bested state averages in some subjects. She said she has achieved success by catering education to each child’s needs.

“You have to know every child, you have to know their attendance data, you have to know what type of teacher they work best with,” Bynum said. “You have to know what their areas of need are.”