This study evaluates the effects of classroom peers on standardized testing achievement for all third- and fourth-grade students in the Philadelphia School District over 6 school years. With a comprehensive individual-and multilevel data set of all students matched to teachers, classrooms, and schools, two empirical strategies are employed. The…

Background/Context: Researchers, policymakers, and practitioners undoubtedly concur that missing school deteriorates student outcomes. And yet, in evaluating the deleterious effects of missing in-school time, empirical research has almost exclusively focused on absences, and the scant amount of empirical literature on tardiness has focused on…