Latent trait models in the study of intelligence

This article examines the potential contribution of latent trait models to the study of intelligence. Nontechnical introductions to both unidimensional and multidimensional latent trait models are given, and possible research applications are considered. Latent trait models are shown to resolve several measurement problems in studies of intellectual change, including ability modification studies and life-span development studies. Furthermore, under certain conditions, latent trait models are found useful for construct validation research, since they can represent an individual differences model of cognitive processing on ability test items. Multidimensional latent trait models are shown to be especially useful as processing models, because they can be used to test alternative multiple component theories of test item processing. Furthermore, multidimensional models can be used to decompose test item difficulty into component contributions and estimate individual differences in processing abilities.