A Comparison of Differential Item Functioning (DIF) Detection for Dichotomously Scored Items Using IRTPRO, BILOG-MG, and IRTLRDIF
This study was designed to provide an empirical comparison of three IRT calibration programs, IRTPRO, BILOG-MG, and IRTLRDIF, all of which can be used for detecting differential item functioning (DIF). The three programs were compared for each of three dichotomous IRT models, the one-parameter logistic, the two-parameter logistic, and the three-parameter logistic models. Results from each of these programs were examined using data from a test designed to predict high school graduation test results in a large Southeastern US state. Results suggested that all three programs detected DIF differently.
ABSTRACT Barbara B. Tillett discusses her career, including her roles as Director, Integrated Library System Program Office, and Chief, Cataloging Policy and Support Office, at the Library of Congress, and her work as a researcher in the area of bibliographic relationships. Topics include the following: current ILS functionality, benefits, and losses; LC's activities in digital futures planning; development of the Functional Requirements for Bibliographic Records; her role in the Joint Steering Committee for Revision of AACR, her part in writing proposals and responses to proposals sent to JSC, and JSC initiatives of the past few years; her work in IFLA and other international organizations and projects; the possible development of a connection between existing international authority files; and other aspects of the emerging internationalization in library catalogs.