1999-08-07Z2011-03-11T08:54:18Zhttp://cogprints.org/id/eprint/824This item is in the repository with the URL: http://cogprints.org/id/eprint/8241999-08-07ZSignificance Test or Effect Size?I describe and question the argument that in psychological research, the significance test should be replaced (or, at least, supplemented) by a more informative index (viz., effect size or statistical power) in the case of theory-corroboration experimentation because it has been made on the basis of some debatable assumptions about the rationale of scientific investigation. The rationale of theory-corroboration experimentation requires nothing more than a binary decision about the relation between two variables. This binary decision supplies the minor premise for the syllogism implicated when a theory is being tested. Some metatheoretical considerations reveal that the magnitude of the effect-size estimate is not a satisfactory alternative to the significance test.Siu L. Chow