In a nutshell, meta-analysis can be described as a set of statisticalmethods for aggregating, summarizing, and drawing inferences from collectionsof thematically related studies. The key idea is to quantify the size,direction, and/or strength of an effect, and to cancel out sampling errorsassociated with individual studies. Meta-analytic techniques have become thestandard methods for aggregating the results from thematically related studiesin various areas. They can be used to describe a research field, to test and/orcompare theories on a high level of abstraction, and to derive conclusionsabout the effectiveness of interventions.

The overall goal of this talk is to provide a hands-on introduction into thedifferent approaches belonging to the umbrella term ´meta-analysis´, to sketchtheir conceptual foundations, and to point to special issues and problems whenevaluating and conducting meta-analytic studies.