A carefully considered study of 113 lottery-based charter schools in the Journal of Economic Perspectives finds “intensive tutoring” is the only charter school practice that producing higher test scores. The study reports: “There is wide variation in impact estimates. To glean what drives this variation, we link these effects to school practices, inputs, and characteristics of fallback schools. In line with the earlier literature, we find that schools that adopt an intensive “No Excuses” attitude towards students are correlated with large positive effects on academic performance, with traditional inputs like class size playing no role in explaining charter school effects. After accounting for performance levels at fallback schools, the relationship between the remaining variation in school performance and the entire No Excuses package of practices weakens. We find that intensive tutoring is the only No Excuses characteristic that remains significant…once the performance levels of fallback schools are taken into account.”