Educational researchers often report effect sizes in standard deviation units (SD), but SD effects are hard to interpret. Effects are easier to interpret in percentile points, but converting SDs to percentile points involves a calculation that is not transparent to educational stakeholders. We show that if the outcome variable is normally…

This article presents methods for using extant data to improve the properties of estimators of the standardized mean difference (SMD) effect size. Because samples recruited into education research studies are often more homogeneous than the populations of policy interest, the variation in educational outcomes can be smaller in these samples than…

The increasing amount of research on the effects of digital technology-based learning on elementary school students' computational thinking ability served as the motivation for this study, which sought to clarify the ambiguous difference in effect size between the variables of digital technology-based learning and computational thinking ability.…