Meta-Analysis: Recent Developments in Quantitative Methods for Literature Reviews

TLDR

Criticisms of meta‑analysis stem largely from misunderstandings of its methods and are equally applicable to traditional narrative reviews. The paper reviews the history and current status of the meta‑analytic enterprise. It outlines the basic steps of meta‑analysis, the role of effect sizes, and discusses effect‑size estimation, heterogeneity, and their practical importance. Meta‑analysis offers advantages such as mapping research domains, contextualizing significance, reducing wasted data, deepening data familiarity, guiding focused questions, and identifying moderators.

Abstract

▪ Abstract We describe the history and current status of the meta-analytic enterprise. The advantages and historical criticisms of meta-analysis are described, as are the basic steps in a meta-analysis and the role of effect sizes as chief coins of the meta-analytic realm. Advantages of the meta-analytic procedures include seeing the “landscape” of a research domain, keeping statistical significance in perspective, minimizing wasted data, becoming intimate with the data summarized, asking focused research questions, and finding moderator variables. Much of the criticism of meta-analysis has been based on simple misunderstanding of how meta-analyses are actually carried out. Criticisms of meta-analysis that are applicable are equally applicable to traditional, nonquantitative, narrative reviews of the literature. Much of the remainder of the chapter deals with the processes of effect size estimation, the understanding of the heterogeneity of the obtained effect sizes, and the practical and scientific importance of the effect sizes obtained.