Accountability and Flexibility in Public Schools: Evidence from Boston’s Charters and Pilots

Using student assignment lottery estimates, a study by Atila Abdulkadiroglu, Joshua Angrist, Susan Dynarski, Thomas Kane, and Parag Pathak unveils large and significant score gains for Boston’s charter students in middle and high school, and in contrast, modest or negative effects for Boston’s pilot school students.

While charter schools and pilot schools both serve as alternatives to traditional public education, further inspection of differences in their key features suggests possible explanations for the discrepancy in student achievement shown by this study.  Pilot schools have some of the independence of charter schools but are in the Boston Public School district and are covered by some collective bargaining provisions. Differences in school structures may originate from collective bargaining agreements in Boston Public Schools which make it relatively expensive for pilot schools to expand instructional hours and staffing which favor teacher seniority over classroom effectiveness.  Charter schools tend to embrace longer day and school year and young teaching staff.  In addition, most of the charter schools in our lottery sample embrace elements of the No Excuses model, an instructional paradigm that is not common in public schools, pilot or otherwise.  Many of the charter schools in the study aspire to boost minority achievement, so a natural benchmark of charter effectiveness examined is the black-white test score gap.  Overall, while lottery estimates show significant gains for charter students, the gains for pilot students are insignificant.  Also, charter schools with binding assignment lotteries appear to generate larger gains than other charters.  The conclusions from the lottery study are supported by the observational study when using the same set of charter schools.