Do charter schools affect school segregation by income? According to new research published this week, public schools in the United States are becoming more separated based on class — and the expansion of charter schools may add to this imbalance.

The opening of even one charter school in a district previously without one leads to a modest uptick in socioeconomic segregation within that district, suggests the research, published in the academic journal Educational Researcher.

The national research matters here because in Washington, charter schools have been pitched as a way to level the playing field for the state’s most disadvantaged students, not exacerbate inequities. The state’s nine charter schools are publicly funded but privately run.

The nascent sector here has attracted many critics, though, who say the schools rob money from traditional public schools and face less oversight.

“A lot of charter schools have a mission to serve underserved populations who tend to be of color, and are more likely to be in poverty,” said Tomas Monarrez, who studies charters and racial segregation, and is a research associate at the Urban Institute, a Washington, D.C.-based moderate-to-left-leaning think tank. Some charters may serve a disproportionate number of low-income students, which could skew the ratio of high- to low-income children in a district’s traditional public schools.

“It’s complicated to say whether that would be a bad thing,” Monarrez added.


It certainly might be, Monarrez and lead researcher David Marcotte agreed. Low-income children who attend charters may benefit from being in a specialized environment. But, Monarrez said, “It’s a bad thing in the sense that there are all these other kids in the system that are not going to get exposed to diversity.”

Charter school advocates cried foul over that interpretation. “I would caution folks to not jump to that conclusion,” said Nathan Barrett, senior director of research and evaluation at the National Alliance for Public Charter Schools advocacy organization. The practical significance of the findings are “really, really small,” he added.

The new study relies on a nationally representative sample and includes data spanning nearly 20 years. It finds that on average, economic segregation in large school districts, including Seattle, spiked by about 15 percent over that period.

The effect of charter schools on this increase is small, though. Lots of factors play into where children enroll, and why some schools have higher concentrations of children living in poverty than others. For instance, parents may move to one neighborhood based on where they’d like their child to attend class. Or, they might choose to home-school or enroll their children in private school. Of all the possible reasons why economic segregation in schools is rising, the research finds that charter schools are tied to 10 percent of the overall increase.

“While charter schools are making the problem worse, they remain a small part of the landscape,” said Marcotte, a professor of public affairs at American University in Washington, D.C.

But why would charters have any effect?

A charter school “introduces the notion of choice,” Marcotte said. Even if parents don’t choose a charter, they may decide to enroll their children somewhere other than their neighborhood school, potentially affecting the district’s socioeconomic makeup. Higher-income families are more likely to take advantage of school choice options, some evidence suggests. But this varies by city and district.


Several studies have probed the economic and racial composition of students who attend charter schools. But the new study is one of the first to point to charters as a source of economic inequality. Other recent research using the same data hints that charter schools add, in small part, to racial segregation.

In the new study, the researchers examined national education data for elementary schools in more than 4,500 school districts. To figure out the effect of charter schools, Marcotte and his colleagues looked at the composition of students in public schools before and after charter schools were first introduced. They also looked at changes as charter school enrollment increased.

They calculated the proportion of students enrolled in free lunch, a proxy for children from low-income homes, compared to those who don’t depend on the food program, at each elementary school.

In some districts, students who qualify for free lunch were more concentrated in particular schools. In other districts, these students were more evenly distributed. After accounting for changes in local poverty rates and other demographics, the researchers found no matter a district’s baseline, adding charter schools made socioeconomic distribution more uneven.

This isn’t surprising, especially in a place such as Washington, said Maggie Meyers, spokesperson for the Washington State Charter Schools Association. In general, charter schools here operate in lower-income neighborhoods and attract a disproportionally high percentage of children in poverty.