Researchers across many fields have called for greater attention to heterogeneity of treatment effects--shifting focus from the average effect to variation in effects between different treatments, studies, or subgroups. True heterogeneity is important, but many reports of heterogeneity have proved to be false, non-replicable, or exaggerated. In…

Modest correlations between teacher-assigned grades and external assessments of academic achievement (r = 0.40-0.60) have led many educational stakeholders to deem grades subjective and unreliable. However, theoretical and methodological challenges, such as construct misalignment, data unavailability and sample unrepresentativeness, limit the…