Multivariate procedures such as the use of generalized least squares (GLS) estimation have been encouraged as appropriate alternatives for handling the dependence (e.g., Becker, 2000; Gleser and Olkin, 2009; Riley, 2009; Raudenbush, Becker, & Kalaian, 1988). The GLS method requires information of the covariance matrices among pairs of effect sizes within studies. However, not all covariance formulae have been derived to address certain dependencies. In addition, the information needed to use the formulae is often not available in individual studies. Most recently, Hedges, Tipton, and Johnson (2010) have suggested and tested robust variance estimation (RVE) for meta-regression. RVE is currently a preferred approach for meta-regression due to its three advantages: (1) it does not require strong assumptions of multivariate normality; (2) it does not require exact values for covariances between dependent effect sizes, and (3) it is robust across both fixed- and random-effects assumptions. Workshop presenters will demonstrate the need for and the use of RVE for meta-analyzing dependent effect sizes. A high-level overview of the material will be provided that will include multiple meta-analytic examples. This workshop is designed to help participants: (1) understand sources and challenges of handling within-study dependence in effect sizes, (2) understand robust variance estimation and its robustness in addressing within-study dependence between effect sizes, (3) conduct meta-regression with Robust-Variance-Estimation using R software, and (4) learn to interpret RVE results reported in R software.
Career Level and Prerequisites: Participants are expected to have completed course work in meta-analysis or have conducted their own quantitative meta-analysis. Fundamental knowledge of univariate meta-analysis is preferred but not required.
Pedagogical Approach: The pedagogical approach will include a PowerPoint presentation, questions and answers, hands-on demonstration, and small-group activities. All data, codes, and materials will be shared with attendees.