catcher is a software program designed to compute the [omega] index, a common statistical index for the identification of collusions (cheating) among examinees taking an educational or psychological test. It requires (a) responses and (b) ability estimations of individuals, and (c) item parameters to make computations and outputs the results of…

This article presents a new method to detect copying on a standardized multiple-choice exam. The method combines two statistical approaches in successive stages. The first stage uses Kullback-Leibler divergence to identify examinees, called subjects, who have demonstrated inconsistent performance during an exam. For each subject the second stage…

A statistical test for detecting answer copying on multiple-choice tests based on Cohen's kappa is proposed. The test is free of any assumptions on the response processes of the examinees suspected of copying and having served as the source, except for the usual assumption that these processes are probabilistic. Because the asymptotic null and…

The Level-11 vocabulary subtest of the Iowa Tests of Basic Skills was analyzed using a two-stage latent trait approach and data set of 2,356 examinees, approximately 11 years of age. It is concluded that the nonparametric approach leads to efficient estimation of the latent trait. (SLD)