A COMPARISON OF LORD CHI-SQUARE, RAJU AREA MEASURES, AND THE LIKELIHOOD RATIO TEST ON DETECTION OF DIFFERENTIAL ITEM FUNCTIONING

This study compares three procedures for the detection of differential item functioning (DIF) under item response theory (IRT): (a) Lord's c hi-square, (b) Raju's area measures, and (c) the likelihood ratio test . Relations among the three procedures and some practical consideratio ns, such as linking metrics and scale purification, are discussed. Dat a from two forms of a university mathematics placement test were analy zed to examine the congruence among the three procedures. Results indi cated that there was close agreement among the three DIF detection pro cedures.