Inside the Black Box: Differences in Achievement Among Edison Schools

The results presented in Chapter Six focus on the average performance of all Edison schools across Edison’s ten-year history of managing schools. Those results also reveal, however, that regardless of which comparison group, baseline score, and operation year is examined, some Edison schools achieve larger gains than comparison schools, whereas others post smaller gains. In this chapter, we present results of analyses that are designed to identify factors related to the different levels of success across Edison schools. Some of the variation in performance among Edison schools was discussed in Chapter Six, where we presented the percentages of schools whose