Plenty of studies have compared the progress of students in charter schools versus traditional public schools. And more than a dozen have examined the “competitive effects” of charters on neighboring district schools. Yet, to our knowledge, no prior study has directly addressed the trillion-dollar question—that is, whether overall achievement increases as the “market share” of charter schools grows.
Rising Tide: Charter School Market Share and Student Achievement, authored by Fordham’s David Griffith, is a first-of-its-kind study that looks at the relationship between “charter market share” and the academic achievement of all students in a given community, including those in traditional public schools. To accomplish this, the report uses data from a new source, which allows researchers to compare English language arts and math scores from thousands of school districts and dozens of different tests.
The study has three findings:
- In large urban areas, higher charter market share is associated with significant achievement gains for black and Hispanic students.
- In suburban and rural areas, higher charter market share is associated with significant achievement gains for Hispanic students, and black students in rural districts also see gains.
- There is no evidence that higher charter market share is associated with achievement gains for white students.
These findings are the basis for three takeaways:
- In general, the district-level evidence suggests that the charter advantage is not attributable to “cherry-picking” or “creaming” the best students.
- Similarly, there is no evidence that charters have a negative effect on the performance of traditional public schools.
- Expanding charter market share in black and Hispanic communities could dramatically reduce racial achievement gaps.
In short, the report is consistent with prior research that suggests black and Hispanic students learn more in charter schools, and that competition from charter schools has a positive, or at worst neutral, effect on traditional public schools.
In other words, a rising tide of charters really does lift all boats.