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Credit: Source: Meredith Richards, Southern Methodist University

Have U.S. schools become more racially segregated in the past two decades? It should seem a simple question to answer, based on the racial composition of schools then and now. But it’s a raging debate among academics, journalists and policy advocates. It turns out that there are different ways to measure segregation or racial diversity and the different measures can sometimes point in opposite directions.

Consider the city of Providence, R.I. In 2000, just over a third, or 36 percent of the district’s 55 public schools were at least 90 percent minority — black, Hispanic or Asian. Fifteen years later, almost three quarters, or 74 percent, of the schools were 90 percent or more non-white. At first glance, that might look like a dramatic resegregation. It was the biggest jump in non-white schools of any district in the nation, according to Meredith Richards, an expert in school segregation at Southern Methodist University, who calculated these figures for The Hechinger Report.

However, when Richards looked at how evenly the students of different races and ethnicities were spread throughout the city’s schools, she found an improvement in student diversity. An index of how evenly all the city’s races were distributed throughout the schools improved by 28 percent. Integration between black and white students improved by 27 percent. That is, the percentage of black, Hispanic, Asian and white students in each school better reflected the diversity of the school age population within Providence.

How can this be? How can you have more non-white schools, where blacks and Hispanics are less likely to interact with whites, while simultaneously have a better distribution of races throughout the schools?

Related: Nearly 750 charter schools are whiter than the nearby district schools

The answer to the riddle has to do with demographic shifts: who moved in and out of Providence between 2000 and 2015. Among the school-age population, Hispanics increased to 64 percent from 50 percent. Meanwhile, both the black and the white populations declined. The white population fell to less than 10 percent of the school district from almost 18 percent. If all the white students were evenly distributed among the schools, every single school in the city should have been designated 90 percent or more minority.

“People believe that measuring racial isolation captures the student experience,” said Richards. “But I don’t like measures that penalize diversity. We should be celebrating diversity. Increases in the proportion of non-whites — calling that segregation — I don’t like that.”

As the share of Hispanics or blacks rise but whites fall in many communities, it’s not uncommon to simultaneously create more non-white schools and yet improve the distribution of students across the schools. Richards highlighted several other school districts where these segregation indicators moved in opposite directions between 2000 and 2015: Waco, Texas; Jackson, Miss.; East Baton Rouge, La.;  and Trenton, N.J.

Each city has its own quirks and they affect these measurements too. In Providence, the school-age population fell by 9 percent and the city closed 13 schools during these 15 years. Merging two schools that leaned toward white increases the percentage of non-white schools. Jackson schools also lost population.

Related: Data show segregation by income (not race) is what’s getting worse in schools

Academic experts tend to point to the evenness measure as a superior indicator of segregation because it can adjust for shifts in the population. But it’s harder to measure and grasp.

The best analogy I’ve come up with is pizza. It’s rather easy to count the number of all-mushroom or all-sausage pizzas and note how those numbers have gone up or down over time. Historically, the number of all-minority, racially isolated schools decreased from the 1960s to the 1980s but has increased steadily since. (It’s noteworthy that you only see this increased racial isolation when you group all minorities together. The number of solely black schools has declined and solely Hispanic schools has remained stable. For example, 23 percent of black students attended a school that was 90 percent or more black in 2000. Fewer than 15 percent of black kids attended an all-black school 15 years later in 2015. Roughly 17 percent of Hispanics attend an all-Hispanic school, a share that hasn’t changed since 2000.)

It’s harder to look at all the toppings in your fridge and calculate if you’ve evenly placed them on all the pizzas you’re making for a party. The math problem becomes more complicated if the amount of each topping in your fridge keep changing. Sociologists and political scientists often use Theil’s index, which can be used to compare a district’s residential population with the student population in each school, and puts each district on a 0 to 1 scale. Zero (0) means no segregation: all students go to a school that exactly mirrors the composition of the district. One (1) means complete segregation. Imagine a town that’s half white and half black with only two schools, and one school is all white and the other is all black. That’s a 1.

When you do this analysis for each school district in the United States, there was a dramatic redistribution of students from the 1960s through the 1980s, spreading blacks and whites more evenly in schools. Schools resegregated slightly in the 1990s and there have been very small improvements in racial integration since the 1990s.

Related: Are schools more segregated than in the 50s?

That’s on average. In many districts, the sausage and mushrooms aren’t being spread across the pizzas together like they used to. For example, Richards found that white and non-white students, who used to attend the same schools in 2000, were more likely to attend separate schools in 2015 in these schools districts: Charlotte-Mecklenberg, N.C., Indianapolis; Hawaii; Sacramento, Calif.; Milwaukee and Detroit. For these districts, the number of non-white schools also increased. By either measure of evenness or racial isolation, it’s getting more segregated in these towns and regions.

Chart showing which districts are seeing segregation increase or decrease compared to those seeing evenness decrease or increase

However, the segregation indicators can also move in the opposite direction here, too. There are districts were the students are less evenly distributed among the schools, and yet there are now fewer all-minority schools. These cities include San Francisco, Richmond, Va., Laredo, Texas, and Seattle.  Again, this can happen because of demographic shifts, such as an influx of white families into the district. A black or Hispanic child might be more likely to attend a school with white children in 2015 but the races are even more clustered into separate schools than they were in 2000.

There are also districts where both segregation indicators are improving. Students are more evenly distributed and the number of racially isolated schools is decreasing. That happened in Hartford, Conn.; Washington D.C.; Pittsburgh; Newark, N.J., and Cleveland. In some cases, such as in Hartford, a court-ordered integration plan reassigned students. In other cases, such as Washington, D.C., there were large population shifts with more whites and Hispanics pouring into the district and blacks exiting, combined with new school choice policies that made it easier for students to attend schools outside of their neighborhood.

The main limitation of this district-by-district analysis is that it only looks at integration or segregation within school districts. Researchers have found increasing segregation across school district lines. Consider a suburban school district with predominantly white families that abuts an urban school district with mostly black and Hispanic families. Within each district, the students might be more equitably distributed. But the urban district might have gained more Hispanics, and reduced its share of white families, so that racial contrast between the two districts has grown starker.

Related: Behind the Latino college degree gap

Integrating across district lines is difficult. School leaders don’t have the authority to assign students to schools outside their district borders. And state politicians are wary of busing students far from their homes.

“Schools alone can’t fix this,” said Sheneka Williams, an expert in school desegregation history at the University of Georgia. “Housing is a place to start. There has to be a federal incentive with housing. If the nation is interested in integrating schools, you have to incentivize people to live together.”

This story about segregation was written by Jill Barshay and produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education. Sign up for the Hechinger newsletter.

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