What is the nature of latent predictors that facilitate diagnostic classification? Rupp and Templin (this issue) suggest that these predictors should be multidimensional, categorical variables that can be combined in various ways. Diagnostic Classification Models (DCM) typically use multiple categorical predictors to classify respondents into…

Whether "psychometric" and "Piagetian" kinds of intelligence are similar is a question of whether they have similar courses of development with age. When using factor analysis to address this issue, age effects must be eliminated in order to assess relations among measured constructs. Reanalyses of previous results were…