META-ANALYSIS OF RANDOMIZED CONTROLLED TRIALS: QUANTITATIVE ASPECTS

Abstract

A meta-analysis combines the results of several studies that address a set of related research hypotheses. Meta-analyses has been taking place in the medical literature, specialy in systematic reviews of randomized control trials. Therefore, there is a need for more works on the underlying statistical methodology. Results from studies are combined using different statistical approaches. One approach frequently used in meta-analysis of randomized controlled trials considers that there is homogeneity across all studies. Regression models with fixed effects are compatible with this assumption. Other approach considers heterogeneity across the studies. Random effects regression models are used in this situation. The present article reviews some quantitative aspects of the meta-analysis.