Addressing dependency in meta-analysis: A companion to Assink and Wibbelink (2016)

This research note elaborates on addressing dependency in effect size data and serves as a companion to our tutorial on fitting three-level meta-analytic models in R (Assink & Wibbelink, 2016). We provide a brief and non-technical description of effect size and standard error interdependency, how the multilevel and the multivariate approach to meta-analysis handle these types of dependency, and the role robust variance estimation methods can have in capturing dependency in effect size data more accurately. Readers are referred to example R code that builds upon the effect size dataset that we presented and analyzed in our tutorial. We conclude that more simulation studies are needed to provide clearer guidelines for modeling dependency in effect size data and urge statisticians to make the available technical literature further accessible to applied researchers.