While the volume of research on charter school achievement has mushroomed in the last five years, most of these studies have used relatively unsophisticated snapshots of student achievement. This paper provides an up-to-date analysis of 14 charter school studies that use the two most rigorous methods: either randomization based on lotteries, or value-added modeling.
The findings show great variety in charter school performance, with charters outperforming in some grade spans/subjects and underperforming in others. Specifically, charters are doing well in elementary reading and middle school math, and poorly in high school math, with mixed performance in other grade spans/subjects. Most states have yet to be studied rigorously, and more research is needed, especially at the high school level.