Detecting redundant items in construction of multiple equivalent test forms using latent Dirichlet allocation

We propose an automatic construction method of multiple equivalent test forms indicated by test information function, and the method reduces the probabilities of selecting redundant items to the same test form. In previous studies, although their methods minimized the different between the test information functions of the constructed test forms, they neglected the content similarities of selected items in the same test form. Therefore, the content similar items have probabilities to be selected into the same test form. This affects the test reliability. The main idea of this paper is to reduce the probabilities by applying a latent Dirichlet allocation in the test construction method to detect the content similarities between the selected items and the remaining items in the item banks.