title: A conceptual and psychometric framework for distinguishing categories and dimensions.
abstract: An important, sometimes controversial feature of all psychological phenomena is whether they are categorical or dimensional. A conceptual and psychometric framework is described for distinguishing whether the latent structure behind manifest categories (e.g., psychiatric diagnoses, attitude groups, or stages of development) is category-like or dimension-like. Being dimension-like requires (a) within-category heterogeneity and (b) between-category quantitative differences. Being category-like requires (a) within-category homogeneity and (b) between-category qualitative differences. The relation between this classification and abrupt versus smooth differences is discussed. Hybrid structures are possible. Being category-like is itself a matter of degree; the authors offer a formalized framework to determine this degree. Empirical applications to personality disorders, attitudes toward capital punishment, and stages of cognitive development illustrate the approach.
authors.affiliation: Department of Psychology, K. U. Leuven, B-3000 Leuven, Belgium. paul.deboeck@psy.kuleuven.ac.be
authors.forename: Paul
authors.initials: P
authors.lastname: De Boeck
authors.forename: Mark
authors.initials: M
authors.lastname: Wilson
authors.forename: G Scott
authors.initials: GS
authors.lastname: Acton
mesh_terms: D002203:Capital Punishment; D003071:Cognition; D006801:Humans; D008960:Models, Psychological; D011584:Psychology / Q000379:methods / Q000706:statistics & numerical data; D011594:Psychometrics