A new study by Scott Imberman and Andrew Johnson shows that special education students benefit from attending charter schools.
Using data from Michigan, the authors identify the effects of charter schools on special education students by comparing special education students who enroll in charter schools early with those who enroll in charter schools late. This research design addresses a common concern in charter school research: students who choose to enroll in charter schools may differ from those who remain in traditional public schools in unobservable ways. Simple comparisons between charter and traditional public school students can therefore be misleading.
To overcome this challenge, Imberman and Johnson compare early charter entrants to late entrants. Because both groups eventually attend charter schools, they are more comparable to one another than to students who never enroll. The effect of charter school attendance is identified by examining differences in outcomes before the late entrants make the switch.
In my view, the study’s two most important findings are:
- Charter schools use special education programs and service assignments that are less intensive and expensive than in traditional public schools.
- Charter schools improve special education students’ academic achievement and attendance.
The authors also conduct a parallel analysis of general education students. They show that the positive effects of charter schools on special education students are similar to the positive effects on general education students.
This study complements recent work by Elizabeth Setren, who examines special education students in Boston who randomly win or lose lotteries to attend charter schools. Because lottery outcomes are random, this design provides especially strong causal evidence that factors other than charter school attendance are highly unlikely to drive the results. Setren likewise finds that charter schools improve test scores for special education students.
Special education students are an important subpopulation. They account for nearly 15 percent of K-12 enrollment in the United States and receive disproportionate funding. Both of these studies find that charter schools serve special education students more effectively. There is now a large and growing body of evidence showing that charter schools outperform traditional public schools for special education.
