5th Annual SRSM Meeting location:Cartagena, Spain date:5-7 July 2010
Multilevel models are increasingly used to model the between-study and the sampling variation, and look for moderator variables to explain the between-study variation. A major advantage of using multilevel models for meta-analysis is their amazing flexibility, allowing fitting models that may better match the kind of data and the research questions. One possibility that is seldom mentioned in the methodological meta-analytic literature or typically is not implemented in software for meta-analysis, is the distinction of a third level of variation to model dependencies between studies (e.g., occurring when several studies stem from the same research group) or within studies (e.g., occurring when within a study multiple samples were drawn).
In the presentation we try to clarify, using real data examples and a simulation study, in which situations three level models are appropriate to solve the problem of dependent effect sizes.