ADVANTAGES OF EXCLUDING UNDERPOWERED STUDIES IN METAANALYSIS - INCLUSIONIST VERSUS EXCLUSIONIST VIEWPOINTS

The authors propose that meta-analysts explicitly specify their resear ch question and their standards for adequate studies to be included, u sing whatever standards they would have applied had they been asked to peer-review the individual studies for funding. Such a proposal corre sponds to previous ones with regard to considerations of sampling, mea surement, design, and analysis adequacy, but the authors of this study extend the proposal to the inclusion of the definition of adequate po wer. They show that if adequate power is defined and then used in revi ewing studies for inclusion in a meta-analysis, excluding those that a re by the meta-analysts' own criterion ''underpowered,'' this strategy would go far toward removing bias due to the ''file-drawer problem'' and resulting misleading research conclusions.