A new study by Susan Dynarski and colleagues examines the effects of a large for-profit charter school operator. Most existing charter school research is on non-profit operators with very little, if any, evidence at the K–12 level on for-profit outfits (although research findings on for-profit institutions at the college level are downright grim).
Analysts leverage randomized admissions lotteries from forty-four National Heritage Academy (NHA) charter schools in Michigan that were oversubscribed between 2002 and 2012 (NHA is the fourth largest for-profit operator in the country). The dataset includes roughly 27,000 applications, and analysts are able to observe at least one post-lottery achievement score for 90 percent of the students in the sample. Scores are observed through grade eight only, in part because most applicants are in kindergarten or first grade. Analysts are able to verify that the lotteries were indeed carried out randomly so they are essentially comparing the outcomes of lottery winners and losers.
Before we get to the findings, here’s a bit of background on NHA. Unlike other charters, almost half of NHA schools are located in suburban areas, forty percent in urban areas, and twelve percent in towns/rural areas. Their students are also less likely to qualify for free or reduced price lunch (61 percent versus 71 percent in other statewide charters) and more likely to be Asian, Hispanic or white than students enrolled in other charters in the state. The NHA schools are all brick and mortar—not online schools—focused on secular virtues modeled on Plato’s cardinal virtues (wisdom, respect, integrity, and so on), and use a “Dean Model,” which pairs an administrative dean—not the principal—with a team of no more than fifteen teachers to render instructional coaching and other supports.
The key finding is that attending a NHA charter school for one additional year is causally linked with greater test score gains in math (about 0.04 standard deviations), with smaller effects in reading that are not statistically significant. There are also no significant differences when it comes to attendance rates, classification as a special education student, and on-time grade progression. Yet when analyzing subgroup differences, they uncover a novel finding: Unlike other charter school studies that find the greatest benefits for low-income or minority students in urban areas, the benefits of attending NHA is concentrated among non-poor students attending their schools outside of urban areas.
Digging further, they attribute much of this difference to dosage in the treatment. In short, poorer kids who won the lottery accumulated just 0.4 more years in an oversubscribed NHA than those who lost the lottery. Specifically, the former are substantially less likely to enroll in NHA the very next fall compared to their advantaged peers. Why? Additional analyses show that distance may be a factor since poorer students are farther away from the nearest NHA school than non-poor kids (in fact, about a half mile farther on average), and as is the case elsewhere, charter schools are not obligated to offer transportation.
Finally, Dynarski and team survey faculty in NHA schools, other charter schools, and the traditional public schools that the NHA students most likely would have attended. Results show that NHA faculty devote more hours per week to math instruction, are more likely to group kids by their math ability, and generally provide teachers with more mentoring—all of which may help explain their key finding.
SOURCE: Susan Dynarski et al., “Estimating the Effects of a Large For-Profit Charter School Operator,” The National Bureau of Economic Research (March 2018).