The measurement of individual change

Models of the Wiener simplex type are described for a single participant's change in a multiwave study. Individual test score change models for continuous scores are based on classical test theory and for discrete scores on the binomial error model. Subsequently, these models are generalized to individual item response change models. In addition, specific models are specified for the item change parameters. The emphasis is on single-subject change models, but they can be extended to population models by making assumptions at the population level.