Modeling multidimensional test data with a unidimensional model can result in serious statistical errors, such as bias in item parameter estimates. Many methods exist for assessing the dimensionality of a test. The current study focused on DIMTEST. Using simulated data, the effects of sample size splitting for use with the ATFIND procedure for…

Proposes a new technique for the evaluation of question difficulty. Suggests that question dispersion by multidimensional scaling models the question-response pattern required by test theory, but without the population density requirements of the traditional methods. Considers the effect on knowledge management functions, including library…