Debunking the charter school attrition myth in New York City

Among the most common complaints critics have of New York City’s charter school is that they have very heavy attrition. Those who would slow the growth of the charter sector portray them as unhappy places that students flee in droves. Charters only appear to be effective, they often claim, because the students who struggle simply leave and re-enter the public sector.

It’s an attractive story for those wedded to the current system. But there’s a problem: Every analysis of actual enrollment numbers finds it to be false. A new report by WNYC is only the latest powerful example.

On Tuesday, WNYC released a report in which they compare the proportion of students who exited each New York City charter school following the 2013-14 school year. Citywide, 10.6 percent of charter school students transferred out that year, compared to 13 percent of students in traditional public schools. That result is similar to my own prior analysis of student attrition in New York City charters and that of the Independent Budget Office.

But perhaps the average masks a hidden exodus out of particular charter schools. To evaluate that, the WNYC report compares each charter’s attrition rate to the average for traditional public schools in the district in which it is located.  

Using the data that WYNC made available online, I calculate that only 22.4 percent of charter schools in New York City had a higher attrition rate than its surrounding district. And even that number is inflated, both by charters with attrition rates that are so close as to be not meaningful, and the likelihood that randomness (one more kid happened to leave for any number of reasons) played a role in their rate falling above the district average. Only 15.8 percent of charters had attrition rates more than 2 percentage points higher than the district.

The nearby figure, created using the data from the new report, illustrates the difference in attrition rate for each charter school and traditional public schools in its surrounding district. Each dot on the figure represents a particular charter school. Dots that fall above the zero have attrition rates higher than the average of their district, dots below the zero have lower attrition rates.

Note: Each circle represents an individual charter school.

 There are a few outlier charters with high attrition rates. But the large majority of New  York City charter schools have attrition rates that are lower than the nearby district. Many charters have attrition rates that are far below the district average.

But is charter attrition strategically designed to push out difficult-to-educate students in order to increase test scores? Recent research has already put that still-far-too-common claim to bed. Separate studies by both me and the IBO show that New York City charter school students who have a disability or are learning English are actually significantly less likely to leave their school if it is a charter than if it is a district school. In another study, I showed that low-performing students exit Gotham charters are similar rates as they exit its district schools.

The new data made available by WNYC illustrates that the general finding that charters have lower attrition than nearby district schools applies to most charter schools, not a small minority of them. The myth that New York City’s charter schools systematically push students out the door simply does not square with any reasonable analysis of the enrollment numbers. It is time for charter school critics to abandon this unsubstantiated talking point.

 Marcus A. Winters is a Manhattan Institute senior fellow and an assistant professor at the University of Colorado Colorado Springs.