01642nas a2200133   4500008004100000245008400041210006900125300001200194490000700206520114900213100002701362700001601389856010301405       2002                        eng d00aDetection of person misfit in computerized adaptive tests with polytomous items0 aDetection of person misfit in computerized adaptive tests with p  a164-1800 v263 aItem scores that do not fit an assumed item response theory model may cause the latent trait value to be inaccurately estimated. For a computerized adaptive test (CAT) using dichotomous items, several person-fit statistics for detecting mis.tting item score patterns have been proposed. Both for paper-and-pencil (P&P) tests and CATs, detection ofperson mis.t with polytomous items is hardly explored. In this study, the nominal and empirical null distributions ofthe standardized log-likelihood statistic for polytomous items are compared both for P&P tests and CATs. Results showed that the empirical distribution of this statistic differed from the assumed standard normal distribution for both P&P tests and CATs. Second, a new person-fit statistic based on the cumulative sum (CUSUM) procedure from statistical process control was proposed. By means ofsimulated data, critical values were determined that can be used to classify a pattern as fitting or misfitting. The effectiveness of the CUSUM to detect simulees with item preknowledge was investigated. Detection rates using the CUSUM were high for realistic numbers ofdisclosed items. 1 aKrimpen-Stoop, E M L A1 aMeijer, R R  uhttp://mail.iacat.org/content/detection-person-misfit-computerized-adaptive-tests-polytomous-items