Due to the size of its charter sector and the high-profile test score gains of some of the city’s charter networks, New York City, with America’s largest school district, has featured prominently in recent charter debates. A new study by Sarah Cordes in Education Next examines how the city’s charter schools affect nearby district schools.
Cordes examines data on state test scores, grade retention, demographics, and school expenditures for 876,731 students in grades three through five over the fourteen-year period from 1996–2010, looking at 584 district schools within one mile of a charter school. She analyzes changes in test score performance of individual students at district schools before and after charters open nearby.
The study finds students in district schools performed 0.02 standard deviations higher, a small but statistically significant gain, in math and reading on annual statewide tests after charters opened within one half mile, while students in co-located district schools, housed in the same building as a charter, performed even better: 0.06 and 0.08 standard deviations higher on reading and math tests, respectively. Cordes finds no positive or negative effects on students in district schools between one half and three miles away. The improvement in test scores was positively affected by increased density of charters (three or more within a one-mile radius) and increased quality of charters, defined as schools with high average scores on fourth grade math and reading exams or being operated by an established, respected network such as KIPP. Other significant academic effects include a reduction in the likelihood of grade retention for students, with the positive effect once again increasing with proximity to the charter school.
To examine what might be changing at schools, Cordes looked at data from the NYC School Survey, a yearly survey of parents, teachers, and students. The results suggest that, after charter schools open nearby, parents and teachers report slightly more positive perceptions of school climate elements like parental engagement, school safety, and academic expectations. Cordes posits that this could be the result of changes in practice at district schools.
Other potential “spillover effects” of charters cited by those concerned about charter expansion include effects on school spending and percentage of high-needs students. Cordes finds that instructional per-pupil spending increased significantly at district schools when charters opened nearby. (The study does not examine what happens to spending on other costs like resources or facilities.) She also found small decreases in enrollment at district schools when charters opened, but no significant changes in student demographics such as race, ethnicity, socioeconomic status, or numbers of English language learners or special education students.
The study is likely to be cited by many charter advocates as definitive proof of charters’ positive effects on district schools everywhere, but Cordes is careful to contextualize her work as significant primarily for charter expansion in New York City. As of 2013, just 11 percent of New York City schools were charters. She notes that whether the results hold true in cities where a higher percent of schools are charters, like Philadelphia or New Orleans, remains to be seen, and also clarifies that her results do not demonstrate whether any of the changes are sustained over time.
Still, the study adds to existing evidence that charter schools may have positive effects on nearby schools. As the nation’s charter sector continues to expand, Cordes’ results should encourage more conversations about how charters and district schools can co-exist and improve together.
SOURCE: Sarah Cordes, “Charters and the Common Good,” Education Next (Spring 2018).
