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.
|Place of Publication||Enschede|
|Publisher||University of Twente, Faculty Educational Science and Technology|
|Number of pages||26|
|Publication status||Published - 2000|
|Name||OMD research report|
|Publisher||University of Twente, Faculty of Educational Science and Technology|
- Adaptive Testing
- Computer Assisted Testing
- Goodness of Fit
- Test Items
- Item Response Theory
van Krimpen-Stoop, E., & Meijer, R. R. (2000). Detection of person misfit in computerized adaptive tests with polytomous items. (OMD research report; No. 00-01). Enschede: University of Twente, Faculty Educational Science and Technology.