USING LOGISTIC-REGRESSION AND THE MANTEL-HAENSZEL WITH MULTIPLE ABILITY ESTIMATES TO DETECT DIFFERENTIAL ITEM FUNCTIONING

Logistic regression has recently been advanced as a viable procedure f or detecting differential item functioning (DIF). One of the advantage s of this procedure is the considerable flexibility it offers in the s pecification of the regression equation. This article describes incorp orating two ability estimates into a single regression analysis, with the result that substantially fewer items exhibit DIF. A comparable an alysis is conducted using the Mantel-Haenszel with similar results. It is argued that by simultaneously conditioning on two relevant ability estimates, more accurate matching of examinees in the reference and f ocal groups is obtained, and thus multidimensional item impact is not mistakenly identified as DIF.