title: Two metamodels of causal effects.
abstract: Two metamodels, termed Model S and Model V, are proposed for definition, measurement, and generalization of quantitative causal effects. The effect is defined as a part change in score in Model S and as a part change in variance in Model V. Two additional changes, total and remainder change, are defined. The latter is due to all other factors or variables than the cause, while total change is the sum of remainder and effect change. Furthermore, it is shown how contrafactual concepts, which imply that some parts of the study situation are supposed to be otherwise, enter into the metamodels. Casual effects are defined and measured in terms of non-contrafactual concepts, except that statistical induction includes contrafactual as well as non-contrafactual inferences. Non-statistical generalization involves both kinds of inferences. Contrafactual definitions are considered inadequate, and a contrafactual interpretation of statistical adjustment is unnecessary and should be replaced by a non-contrafactual one.
authors.affiliation: University of Oslo, Department of Psychology, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Lund
mesh_terms: D000328:Adult; D001288:Attention; D003118:Color Perception; D005556:Form Perception; D006801:Humans; D011939:Mental Recall; D011597:Psychomotor Performance; D012153:Retention, Psychology; D014706:Verbal Learning