ERIC Number: ED350318
Record Type: RIE
Publication Date: 1992-Apr
Reference Count: N/A
Detecting Differential Item Functioning Using the Rasch Model with Equivalent-Group Cross-Validation.
Miao, Chang Y.; Kramer, Gene A.
An approach to detecting differential item functioning using the Rasch model with equivalent-group cross-validation was investigated. College students taking the Dental Admission Test, were divided by gender (936 females and 1,537 males) into 2 different samples. Rasch analyses were performed on both samples. Data were recalibrated after misfitting persons and items were removed. Resulting difficulties from the two samples were compared, and some potentially biased items were identified. Each sample was then randomly divided into two equivalent samples, resulting in four groups, two of males and two of females. Rasch calibrations were again performed. Items were rank-ordered, and items with the same rankings were selected for equating. Link constants were calculated by selecting one of the four groups as the ground scale. Using the t-test, item-by-item comparisons were conducted within each group pair after the equating. Different difficulty calibrations were compared across the different groups. The significantly different difficulties may have been caused by sampling fluctuation if the t-value was significant when comparing groups with the same gender membership. Finally, identified items were examined for bias. The final set of biased items was then distributed to the test construction committee for possible modifications. One table contains descriptive statistics from the analysis. (Author/SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A
Identifiers: Cross Validation; Rasch Model; T Test
Note: Paper presented at the Annual Meeting of the American Educational Research Association (San Francisco, CA, April 20-24, 1992).