Review of Measuring Diversity in Charter School Offerings

Program variation has long been touted as a charter school advantage, so a recent AEI report rates the diversity of charter school programs in 17 major cities. Examining charter school websites, the report finds the schools evenly split between “Specialized” schools (e.g., no excuses, STEM, or Arts) and “General” schools. It finds small to moderate correlations between city demographics and certain types of charter schools but also finds that specialized schools tend to morph into homogenized general schools. The report has several weaknesses. It claims superior diversity for charter schools but doesn’t empirically compare charter offerings with those of traditional public schools, which typically include many diverse options. Similarly, the introduction claims charter schools are hamstrung by red tape, but this is not addressed in the report. Also, as acknowledged in the report, coding schools based on website descriptions is an error-prone enterprise, yet no check of the accuracy of the data is provided. As the correlations between charter schools and city demographics are based on only 17 cases (cities are the unit of analysis), this is too weak a base to support the report’s conclusions. Fundamentally, the report does not make the case for its major claims, and thus has only minimal utility.