As researchers continue to examine the growing number of charter schools in the United States, they have focused attention on the significant heterogeneity of charter effects on student achievement. Our article contributes to this agenda by examining the achievement effects of virtual charter schools vis-à-vis brick-and-mortar charters and…

Researchers are increasingly using comparative interrupted time series (CITS) designs to estimate the effects of programs and policies when randomized controlled trials are not feasible. In a simple interrupted time series design, researchers compare the pre-treatment values of a treatment group time series to post-treatment values in order to…