This article reviews the origins and use of the terms quasi-experiment and natural experiment. It demonstrates how the terms conflate whether variation in the independent variable of interest falls short of random with whether researchers find, rather than intervene to create, that variation. Using the lens of assignment--the process driving…

Flipped classrooms (FCs) in K-12 schools are growing in popularity. However, previous studies have reported inconsistent findings on the effects of FCs, and the conditions under which FCs are effective remain unclear. This three-level meta-analysis synthesized the effects of FCs versus traditional classrooms (TCs) on various learning domains among…