Meta-Analysis in Educational Research: A Primer on Concepts and Applications

Meta-analysis is a statistical process used to synthesize the results of multiple independent studies on answering a research question. Imagine you wish to understand the impact of immediate feedback versus delayed feedback in online learning, and you specifically want to know the magnitude of the impact, you could look at the effect size. Now, imagine the extant research has dozens of articles with different effect sizes for their outcomes, and they vary. What can you do? How would you statistically assess the true impact of the intervention? Rather than focusing on one research intervention, a synthesis of multiple studies through statistical means allows researchers to improve power compared to single studies, look for patterns across studies, and provide a more precise estimation of the effect size. As a special case of a systematic review, meta-analyses seek to provide transparent and reproducible processes. In contrast to narrative reviews, meta-analyses provide transparent and reproducible processes by employing a methodological and quantitative approach to the educational research problem. Meta-analyses can accommodate a wide range of quantitative research designs so long as a unified effect size can be extracted from each study to build the overall statistical model.