The DIF-Free-Then-DIF Strategy for the Assessment of Differential Item Functioning

Autor/inn/en	Wang, Wen-Chung; Shih, Ching-Lin; Sun, Guo-Wei
Titel	The DIF-Free-Then-DIF Strategy for the Assessment of Differential Item Functioning
Quelle	In: Educational and Psychological Measurement, 72 (2012) 4, S.687-708 (22 Seiten)Infoseite zur Zeitschrift PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0013-1644
DOI	10.1177/0013164411426157
Schlagwörter	Test Bias; Test Items; Item Response Theory; Evaluation Methods; Computer Software; Accuracy; Simulation; Error of Measurement + Suchen Sie Ihr Suchwort? Testkritik; Test content; Testaufgabe; Item-Response-Theorie; Simulation program; Simulationsprogramm; Messfehler
Abstract	The DIF-free-then-DIF (DFTD) strategy consists of two steps: (a) select a set of items that are the most likely to be DIF-free and (b) assess the other items for DIF (differential item functioning) using the designated items as anchors. The rank-based method together with the computer software IRTLRDIF can select a set of DIF-free polytomous items very accurately, but it loses accuracy when tests contain many DIF items. To resolve this problem, the authors developed a new method by adding a scale purification procedure to the rank-based method and conducted two simulation studies to evaluate its performances on DIF assessment. It was found that the new method outperformed the rank-based method in identifying DIF-free items, especially when the tests contained many DIF items. In addition, the new method, combined with the DFTD strategy, yielded a well-controlled Type I error rate and a high power rate of DIF detection. In contrast, conventional DIF assessment methods yielded an inflated Type I error rate and a deflated power rate when the tests contained many DIF items favoring the same group. In conclusion, the simulation results support the new method and the DFTD strategy in DIF assessment. (Contains 4 tables and 2 figures.) (As Provided).
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Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10