Student demographics in traditional district schools largely reflect patterns of housing availability and affordability within neighborhoods. Much of that is due to strict attendance zoning. Charter schools can break this pattern by offering open, unzoned enrollment to all students in a given city. But as charters continue to expand, school leaders have had to deal with charges of racial segregation. Unlike the forced segregation of an earlier era, parents are free to opt into or out of a charter based on its racial composition—or anything else for that matter. Still, whether the expansion of charters alters the demographics of neighborhood-assigned district schools remains a non-trivial question.
A recent study conducted by Sarah Cordes and Agustina Laurito examines the consequences of charter school expansion in New York City from 2000 to 2017 on both school-level and neighborhood-level diversity. Due to its historically high level of residential and school segregation, as well as its fast growing charter sector, Gotham is an ideal location for such a query.
The sample included all traditional public elementary schools (TPS) that contained a fourth grade in the twenty-nine community school districts that also had at least one charter elementary operating within its boundaries at any time during the observation period. These selection criteria resulted in a sample of 742 schools and nearly 68,000 school-grade-year observations. They use Common Core of Data, U.S. Census data, and school zone shape files to gather student data by grade level and race/ethnicity, as well as school location data and racial composition measures at the school-zone level.
To disentangle the effects of charters on both TPS and neighborhood characteristics, they use a difference-in-differences design that utilizes two sources of variation: 1) the phase-in of charter schools, as most begin by offering kindergarten and then expand by an additional grade each year, and 2) expansion in the relative size of the charter sector as more charter schools open within the district. They are therefore comparing the racial composition of TPS-grades that are experiencing changes in charter school exposure to the racial composition of TPS-grades within the same school experiencing no changes in charter school exposure. Student demographics in grades that don’t experience changes in charter school exposure serve as a strong counterfactual since they should not be directly affected by charter expansion but should reflect other demographic changes occurring in schools and neighborhoods.
To examine the relationship between school and neighborhood segregation, the researchers analyzed the difference between the racial composition of the TPS and that of the school-age population residing in the neighborhood where the school is located, meaning they are observing the extent to which school and neighborhood demographic changes match. For the diversity measure, a value of 0 indicates no diversity (all students in a school-grade are the same race) and a 1 indicates that all four racial and ethnic groups—White, Black, Hispanic, and Asian or other race—are equally represented at 25 percent each.
Cohodes and Laurito found a small but statistically significant positive effect of the share of charter seats on TPS diversity. Specifically, a 10 percentage-point increase in the share of charter seats in a grade results in a 2.9 percentage-point increase in the racial diversity score. This change is driven by an increase in the share of White and Hispanic students and a decrease in the share of Black students enrolled in TPS-grades after charter expansion—not surprising given charter schools’ popularity with Black families.
Further, this increase in diversity occurs on a margin that also affects intense segregation, defined as a school-grade that is 90 percent or more of the same race. Specifically, a 10- percentage point increase in charter seats lowers the likelihood of intense segregation by about 3 percentage points, which largely reflects reductions in the probability that a TPS-grade is over 90 percent Black. In terms of neighborhood diversity, changes largely mirror changes in school diversity except that the latter is increasing even faster than the former.
The authors conclude that their “results suggest that charter schools increase diversity in TPSs primarily by reducing the share of Black students and increasing the share of White students enrolled in these schools.” So to those worried that charter schools amount to “white-flight” academies, you can rest easy. White students are far from “flocking to” charter schools. Moreover, this study finds that more diversity—not more segregation—is what is occurring in TPS.
SOURCE: Sarah A. Cordes and Agustina Laurito, “Choice and Change: The Implications of Charter School Expansion for School and Neighborhood Diversity in NYC,” retrieved from the Annenberg Institute at Brown University (April 2022).