Meta-analysis: an introduction using regression models

Research synthesis of evaluation findings is a multistep process. An investigator identifies a research question, acquires the relevant literature, codes findings from that literature, and analyzes the coded data to estimate the average treatment effect and its distribution in a population of interest. The process of estimating the average treatment effect is meta-analysis. Meta-analysis is gaining popularity across the social sciences, but introductions and even advanced treatments of the subject are often formula-driven. Researchers, who apply formulas without understanding, risk both misapplication and misinterpretation. This article derives formulas used in meta-analysis using standard regression models so this article seeks to introduce readers with an understanding of regression analysis to meta-analysis, intending thereby to motivate and facilitate a deeper reading of the meta-analysis literature.