Differential Item Functioning (DIF) Detectioninusbnfor Chemistry Subject Through Lord’s Chi Square Method
The importance of Differential Item Functioning (DIF)detection is to select test questions which precisely measures a student’s ability without taking sides in particular students and later produces real qualified questions. Thereby, this research is to detect DIF in National Standard School Exam or known as USBN for Chemistry Subject toward gender group using item response theory. Equally important, this research is an exploratory which reveals question items with DIF detection. The subjects of this research include all answer sheets fromUSBN participants for Chemistry Subject with the total of 676 students. DIF in the questions is detected by using Lord’s Chi Square method based on item response theory. Considering the result of data processing through item response theory in three-parameter logistic model using Lord’s Chi Square method from 35 question items, there are 19 items which are indicated as gender bias such as item 2, 3, 8, 9, 12, 14, 15, 16, 18, 20, 21, 24, 25, 26, 27, 30, 31, 32, and 35. It is clearly that those items are disposed to female students’ group.
Keywords- DIF, gender, item response theory, Lord’s Chi Square method