Detection Of Dif Across Different Academic Backgrounds And Genders In CET-4

The present study investigated the presence of differential item functioning (DIF)in the College English Test Band4(CET-4) across different academic backgroundsand genders with two approaches called Mantel-Haenszel (MH) and LogisticRegression (LR). The results of the study indicated, by both approaches, that eightitems were detected as functioning differentially for the Humanity and Science groups,and seven items were detected as showing DIF for the male and female groups. Somepossible underlying reasons for DIF items were attempted to discuss from the aspectsof content and other more specific factors. However, the number of DIF items acrossdifferent academic backgrounds is almost even, so is the number between gendergroups. Besides, three experts were invited to make judgment on large DIF items. Bystatistical methods and external judgment, the test paper could thus be taken aswell-designed with the absence of bias. Some implications and suggestions for futureresearches were also addressed.