Assessment of Differential Item Functioning in Testlet-Based Items Using the Rasch Testlet Model

Autor/inn/en	Wang, Wen-Chung; Wilson, Mark
Titel	Assessment of Differential Item Functioning in Testlet-Based Items Using the Rasch Testlet Model
Quelle	In: Educational and Psychological Measurement, 65 (2005) 4, S.549-576 (28 Seiten)Infoseite zur Zeitschrift PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0013-1644
DOI	10.1177/0013164404268677
Schlagwörter	Test Format; Test Bias; Item Response Theory; Item Analysis; Simulation; Test Items; Evaluation Methods; Measurement Techniques; Models + Suchen Sie Ihr Suchwort? Testentwicklung; Testkritik; Item-Response-Theorie; Itemanalyse; Simulation program; Simulationsprogramm; Test content; Testaufgabe; Messtechnik; Analogiemodell
Abstract	This study presents a procedure for detecting differential item functioning (DIF) for dichotomous and polytomous items in testlet-based tests, whereby DIF is taken into account by adding DIF parameters into the Rasch testlet model. Simulations were conducted to assess recovery of the DIF and other parameters. Two independent variables, test type and anchor item method, were manipulated. The proportion of DIF items in the tests was set at approximately 40%. All parameters could be accurately recovered whenever the model was the generating model or only one DIF-free item was set as the anchor and all other items were treated as presumed DIF items. The bootstrap method is recommended to approximate the standard errors of the estimators for the DIF parameters so that the Wald statistic can be computed to test the null hypothesis of no DIF. Alternatively, the likelihood ratio test can be used to test the same hypothesis by comparing a full model with the DIF parameter and a reduced model without it. (Author).
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Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10