A NEW PROCEDURE FOR DETECTION OF CROSSING DIF

The purpose of this paper is to present a hypothesis testing and estim ation procedure, Crossing SIBTEST, for detecting crossing DIF. Crossin g DIF exists when the difference in the probabilities of a correct ans wer for the two examinee groups changes signs as ability level is vari ed. In item response theory terms, crossing DIF is indicated by two cr ossing item characteristic curves. Our new procedure, denoted as Cross ing SIBTEST, first estimates the matching subtest score at which cross ing occurs using least squares regression analysis. A Crossing SIBTEST statistic then is used to test the hypothesis of crossing DIF. The pe rformance of Crossing SIBTEST is evaluated in this study.