Comparing the sample-weighted and unweighted meta-analysis: an applied perspective
用实际数据比较了样本加权和未加权的元分析方法，发现未加权方法在应用中的优势并不总是成立，两种方法可能导致不同的实质性结论。
An extensive comparison of the sample-weighted method (Hunter & Schmidt, 1990), and a newer unweighted method (Osburn & Callender, 1992) of meta-analysis is presented using actual data. Several of the advantages of the unweighted method predicted by Osburn and Callendar’s simulation research did not always hold in actual application. Specifically, the unweighted method did not always produce larger estimates of observed variance, credibility intervals, and confidence intervals than the sample-weighted method when large sample outliers are present. Also, Osburn and Callender’s research on mean sampling variance formulae did not generalize to meta-analysis using the average correlation estimator to measure sample error variance. Finally, results show that while both methods may generate similar parameter and variance estimates in primary meta-analysis, they may lead researchers to reach different substantive conclusions in the analysis of moderators.