A recently released study shows Newark’s largest charter school networks give students a boost in their test scores. WBGO’s Ang Santos spoke with senior fellow with the Manhattan Institute for Policy Research Marcus Winters by phone. Winters, an associate professor at Boston University authored the report.

Ang Santos: Your study looks at data from the years 2014 to 2018 and shows students who enrolled at schools run by Newark’s two largest charter operators saw improved and lasting gains in test scores, what was the process for coming to that conclusion?

Marcus Winters: The study that we do is similar to a randomized trial. So, what we did is take advantage of the way that Newark assigns students to schools through the common enrollment system. Embedded in that is a randomized process based on the student’s preferences and the school’s preferences. We use that in order to compare the outcomes of students that were offered a charter school seat to those who were not. In a way that holds constant everything else about the individual. We’re doing a real apple to apples comparison with students that have been assigned to charter schools and students that weren’t. When we get the differences between those groups, we can be really confident that the benefits that we see from the charter schools is from attending the charter schools itself. It’s not from other factors that are related to wanting to go to a charter school.

AS: What did you find?

MW: What we found was overall there is a large and statistically significant benefit from enrolling into a Newark charter school that participates in the common enrollment system. We can say less about the schools that don’t participate in that system. But the large majority of schools do participate. We saw the largest positive effect for students attending schools operated by either KIPP or Uncommon. These are the TEAM charter schools and the North Star charter schools. They had an especially large positive effect. When we looked at the other schools that are not operated by KIPP and Uncommon you get a hint of a positive effect but on average it’s not particularly significant. I think it’s important though to keep in mind when we look at that result is that we’re combining a very large variety of schools. We can say on average attending one of those participating schools other than KIPP or Uncommon didn’t have a meaningful effect on test scores, but surely some of them individually are probably more effective than others.

AS: Does this study look at the impact of Newark’s charters on the traditional public-school district?

MW: No, we don’t look at the effect that the charter sector has had. It’s just not something we looked at and studied. It is a really interesting question. It’s something researchers have looked at in other areas. Overall, we tended to find that as school choice from charter schools and other school choice programs increases, it tends to have no effect on the quality of the local public schools or a very small positive effect. It’s not something we were looking at in Newark but I think it would be really interesting to do.

AS: In a city like Newark where the charter versus traditional school debate rages on, in what way does your study, if at all, weigh in on that conversation?

MW: What I’m hoping to get out of the study is some concrete information to help inform that conversation. I think my study shows really clear evidence that on average students who are enrolling in the charter sector are doing substantially better than if they would have enrolled in one of the traditional public schools. The fact that you get these different results from KIPP and Uncommon is interesting because those are the school that have grown the most and are the largest within the city. That result is consistent with what has been found in other cities including Boston and Denver. I think it adds important information to trying to understand when we see better test scores in the charter sector than the public sector that it can be misleading. That can be caused by the types of kids that are enrolled there. My study gets around that. It gives us a real estimate of the effect of attending a charter school. With that said it doesn’t answer all of the questions. There are lots of things we want schools to do other than raise test scores. There are lots of other factors that go into the discussion of charter schools and their growth. Especially in Newark where the charter sector is so large. My goal is to add real information to how effective these schools have been to this point. Hopefully to policy makers in the community this information can be helpful to inform that conversation.

To see the complete study click here.