ESTIMATING MAGNITUDE OF EXPERIMENTAL EFFECTS

Discusses the increasing awareness that the mere statistical significance of an experimental effect is insufficient to warrant the conclusion that the effect is large and practically important. A number of related measures of the magnitude of experimental effects which can be applied to the results of a 1-way analysis of variance but not to the results of a more complicated design are available. The proper measure for a complex design depends on whether other factors are fixed or random, and the uncritical following of advice given in the literature can result in serious over- or underestimation of the magnitude of experimental effects. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.