Multidimensional scaling and factor models of test and item responses

This article discusses 2 alternatives to the factor model for test or item responses. From the two alternative models, proximity measures are derived so that the proximity measures are within an additive constant of squared euclidean distances between item or test parameters. Hence, multidimensional scaling (MDS) can be used to estimate the item parameters in the alternative models. Solutions that are based on the models are compared. In light of the response models, interpretation and appropriateness of factor and MDS solutions are discussed.