The Charter School Attrition Myth
Charter-school critics in New York City and elsewhere often claim that these publicly-funded, privately-run schools of choice frequently push low-performing students out the door. This view was given additional policy salience when recently echoed by Schools Chancellor Carmen Fariña.
Given the frequency and assuredness of such criticism, one would assume that it was backed by evidence more substantial than mere anecdotes. To date, however, no empirical evidence has been mustered to suggest that charters systematically remove, or pressure out, low-performing students.
In a new study for the Manhattan Institute, I use student-level administrative data to examine the movement of the city's charter and traditional public school students over six years, assessing how mobility patterns relate to students' prior test scores.
My results confirm that low-performing students are more likely to exit charters than higher-performing students. But I also find that low-performing students in traditional public schools demonstrate similar attrition patterns. In other words, low-performing students are more likely to exit their schools regardless of school sector attended. The relevant question, then, is whether low-performing students are more likely to exit charters than traditional public schools.
The answer to that question, my findings reveal, is “no”: Low-performing students are just as likely to exit a traditional public school in New York City as they are to exit a charter school. Such results build upon my previous body of empirical research examining attrition patterns in NYC charter and traditional public schools. Here, too, the evidence paints a picture at odds with the assertions of charter critics.
In fact, I found that both students with special needs and those classified as learning English are significantly less likely to exit charters than traditional public schools. Attrition overall is also lower in charter schools than in traditional public schools. A recent report by the Independent Budget Office found similar results.
The enrollment numbers simply don't square with the claim that charter schools systematically remove low-performing or otherwise difficult-to-educate students. If attrition rates are concerning in the the city's charter school sector, they are at least as worrisome in its traditional public schools.
Nonetheless, charter school critics are sure to note that low-performing students who leave charters are often not “backfilled” (i.e., replaced within the departed school), which tends to boost charters' test scores relative to traditional public schools. The enrollment patterns, then, make direct comparisons of test scores in charter and traditional public schools unfair.
There are a host of reasons that average test scores should not be the principal measuring stick of the charter sector's effectiveness. It is precisely because charter schools serve different populations of students and experience different enrollment patterns that we must rely on strong empirical research to assess their impact. Extensive empirical research of this type consistently finds that students benefit from attending NYC charters over traditional public schools. In no way does failure to backfill put into question this robust empirical result.
As NYC's charter sector expands, it is appropriate to discuss whether charters can do even more to recruit and serve difficult-to-educate students. Issues such as backfill and adopting a more uniform application process deserve serious consideration.
But conversations over the relative merits of charter schools need to be grounded in facts, not anecdotes. For those who continue to insist that New York City's charters systematically remove low-performing students, the burden is now squarely on their shoulders to provide empirical evidence to support their claim. As the facts stand, however, their argument is plainly contradicted by rigorous analysis of NYC student enrollment and test score data.
This piece originally appeared in New York Daily News
This piece originally appeared in New York Daily News