Research Seminar
Detecting and modelling item-position effects using a differential item functioning and a linear logistic test model frameworkDries DebeerKU Leuven | |
| Abstract: | In achievement testing, the use of alternate test forms in which the same set of items is presented in orders that differ across forms, is a common strategy to prevent copying and to enhance test security. Consequently, items are administered in different positions in different test forms. Psychometric literature, however, shows that such changes in item position can threaten measurement invariance and item parameter invariance assumptions. A variety of different methods and approaches have been designed to detect and model item position effects. However, these methods address only the item-side or only the person-side of the issue. Therefore, an integrated IRT-based approach is proposed combining the logic of Differential Item Functioning (DIF) models and the Linear Logistic Test Model (LLTM). The proposed approach detects and models item-position effects while taking into account the person and the item side simultaneously, by means of a random weight position effect. After a brief discussion of the different methods in the literature, the new approach is illustrated with an application in educational measurement. |
| Date: | Tue May 17, 12:15 pm - 1:15 pm |
| Place: | room 02.60 (Department of Psychology, Tiensestraat 102, 3000 Leuven) |