ERIC Number: ED450126
Record Type: Non-Journal
Publication Date: 2000
Reference Count: N/A
Detection of Person Misfit in Computerized Adaptive Tests with Polytomous Items. Research Report.
van Krimpen-Stoop, Edith M. L. A.; Meijer, Rob R.
Item scores that do not fit an assumed item response theory model may cause the latent trait value to be estimated inaccurately. For computerized adaptive tests (CAT) with dichotomous items, several person-fit statistics for detecting nonfitting item score patterns have been proposed. Both for paper-and-pencil (P&P) test and CATs, detection of person misfit with polytomous items has hardly been explored. In this simulation study, the theoretical and empirical null distributions of a person-fit statistic for polytomous items are compared for P&P tests and CATs. Results show that the empirical distribution of this statistic was close to the standard normal distribution, for both P&P tests and CATs. Also statistics that are especially designed for a CAT are proposed. In these statistics observed and expected item scales are compared using cumulative sum (CUSUM) procedures. Results show that the critical values of the CUSUM were symmetric around zero and similar across latent trait values. Moreover, the results show that for the CUSUM procedure fixed critical values for all examinees can be used. (Contains 5 tables and 40 references.) (Author/SLD)
Descriptors: Adaptive Testing, Computer Assisted Testing, Goodness of Fit, Item Response Theory, Scores, Test Items
Faculty of Educational Science and Technology, University of Twente, TO/OMD, P.O. Box 7500 AE Enschede, The Netherlands.
Publication Type: Reports - Research
Education Level: N/A
Sponsor: Law School Admissions Council, Newtown, PA.
Authoring Institution: Twente Univ., Enschede (Netherlands). Faculty of Educational Science and Technology.