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Abstract

The differential item functioning (DIF) detection in polytomous response items is an area of study of recent interest. Cohen and colleagues proposed a polytomous extension of the Lord statistic and the Raju exact area measures, when the items fit the graded response model. This study examined the effects of test purification in detecting DIF by means of polytomous extensions of the Raju area measures and the Lord statistic. The factors manipulated were percentage of DIF items in the test (5%, 10%, and 20%), amount of DIF (0.2, 0.4, and 0.8), sample size (250, 500, and 1,000) and test purification (noniterative versus two-stage). The results of this study suggest that the use of the two-stage equating procedure with Z(SA) and χ²-LORD reduces the percentage of false positives and improves the detection of DIF.

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References

Baker, F. B. (1992). Item response theory: Parameter estimation techniques. New York: Marcel Dekker.

Baker, F. B. (1993). EQUATE 2.0: A computer program for the characteristic curve method of IRT equating. [Computer program]. Madison: University of Wisconsin, Laboratory of Experimental Design.

Candell, G. L. , & Drasgow, F. (1988). An iterative procedure for linking metrics and assessing item bias in item response theory. Applied Psychological Measurement, 12, 253-260.

Chang, H. H. , & Mazzeo, J. (1994). The unique correspondence of item of the item response functions in polytomously scored item response models. Psychometrika, 59, 391-404.

Cohen, A. S. , Kim, S. H. , & Baker, F. B. (1993). Detection of differential item functioning in the graded response model. Applied Psychological Measurement, 17, 335-350.

French, A. W. , & Miller, T. R. (1996). Logistic regression and its use in detecting differential item functioning in polytomous items. Journal of Educational Measurement, 33, 315-332.

Lautenschlager, G. J. , Flaherty, V. L. , & Park, D. (1994). IRT differential item functioning: An examination of ability scale purifications. Educational and Psychological Measurement, 54, 21-31.

Lord, F. M. (1980). Applications of item response theory to practical testing problems. Hillsdale, NJ: Lawrence Erlbaum.

Mellenbergh, G. J. (1989). Item bias and item response theory. International Journal of Educational Research, 13, 127-143.

10.

Miller, M. D. , & Oshima, T. C. (1992). Effect of sample size, number of biased items and magnitude of bias on a two-stage item bias estimation method. Applied Psychological Measurement, 16, 381-388.

11.

Miller, T. R. , & Spray, J. A. (1993). Logistic discriminant function analysis for DIF identification of polytomously scored items. Journal of Educational Measurement, 30, 107-122.

12.

Park, D. G. , & Lautenschlager, G. J. (1990). Improving IRT item bias detection with iterative linking and ability scale purification. Applied Psychological Measurement, 14, 163-173.

13.

Potenza, M. T. , & Dorans, N. J. (1995). DIF assessment for polytomously scored items: A framework for classification and evaluation. Applied Psychological Measurement, 19, 23-37.

14.

Raju, N. S. (1988). The area between two item characteristic curves. Psychometrika, 53, 492-502.

15.

Raju, N. S. (1990). Determining the significance of estimated signed and unsigned areas between two item response functions. Applied Psychological Measurement, 14, 197-207.

16.

Samejima, F. (1969). Estimation of latent ability using a response pattern of graded scores. Psychometric Monograph Supplement 1.

17.

Stocking, M. L. , & Lord, F. M. (1983). Developing a common metric in item response theory. Applied Psychological Measurement, 7, 201-210.

18.

Thissen, D. (1991). MULTILOG user’s guide (Version 6.0) [Computer program]. Chicago: Scientific Software.

19.

Thissen, D. , Steinberg, L. , & Wainer, H. (1993). Detection of differential item functioning using the parameters of item response models. In P.W. Holland & H. Wainer (Eds.), Differential item functioning (pp. 67-113). Hillsdale, NJ: Lawrence Erlbaum.

20.

Zwick, R. , Donoghue, J. , & Grima, A. (1993). Assessment of differential item functioning for performance tasks. Journal of Educational Measurement, 30, 233-251.

Two-Stage Equating in Differential Item Functioning Detection under the Graded Response Model with the Raju Area Measures and the Lord Statistic

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