This study examined the contribution of classroom format on teaching effectiveness and achievement in English language arts (ELA) and mathematics. Secondary data analyses of the Measures of Effective Teaching database included 464 US classrooms. Classrooms were defined as self-contained if a generalist teacher provided instruction on all subjects…

Using richly detailed data on fourth- and fifth-grade students in the North Carolina public school system, I find evidence that students are assigned to classrooms in a non-random manner based on observable characteristics for a substantial portion of classrooms. Moreover, I find that this non-random assignment is statistically related to class…