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ERIC Number: ED382658
Record Type: Non-Journal
Publication Date: 1994-Aug
Pages: 21
Abstractor: N/A
Reference Count: N/A
The Effect of the Probability of Correct Response on the Variability of Measures of Differential Item Functioning. Program Statistics Research Technical Report No. 94-4.
Zwick, Rebecca
The Mantel Haenszel (MH; 1959) approach of Holland and Thayer (1988) is a well-established method for assessing differential item functioning (DIF). The formula for the variance of the MH DIF statistic is based on work by Phillips and Holland (1987) and Robins, Breslow, and Greenland (1986). Recent simulation studies showed that the MH variances tended to be larger when items were administered to "examinees" who were randomly selected from a population than when items were administered adaptively. An analytic perspective shed some light on this puzzling result. Although the general form of the MH variance is complex and does not provide an intuitive understanding of the phenomenon, application of certain Rasch model assumptions yields a simple expression that appears to explain the difference in variances for adaptive versus nonadaptive administration. One table, two figures. (Contains 13 references.) (Author)
Publication Type: Reports - Evaluative
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: Educational Testing Service, Princeton, NJ.