This paper examines data on 39 charter schools and correlates these data with school effectiveness. We find that class size, per-pupil expenditure, teacher certification, and teacher training—are not correlated with school effectiveness. In stark contrast, we show that frequent teacher feedback, the use of data to guide instruction, high-dosage tutoring, increased instructional time, and high expectations—explains approximately 45 percent of the variation in school effectiveness.
Dobbie, W., & Fryer Jr, R. G. (2013). Getting beneath the veil of effective schools: Evidence from New York City. American Economic Journal: Applied Economics, 5(4), 28-60.