The Effects of Referent Item Parameters on Differential Item Functioning Detection Using the Free Baseline Likelihood Ratio Test
Tóm tắt
The purpose of this simulation study is to investigate the effects of anchor subtest composition on the accuracy of item response theory (IRT) likelihood ratio (LR) differential item functioning (DIF) detection (Thissen, Steinberg, & Wainer, 1988). Here, the IRT LR test was implemented with a free baseline approach wherein a baseline model was formed by freeing all items except a referent or anchor subset and examining the changes in fit with respect to a series of models wherein 1 item at a time was constrained in addition to the referent(s). The results clearly indicated that the composition of the anchor subtest is important for accurate DIF detection. It was found that using a single highly discriminating rather than a low discriminating referent greatly enhanced the power of the procedure. Moreover, in conditions involving small DIF or smaller sample sizes or both, power appeared to improve when a group of highly discriminating referents was used. These findings have implications for applied research involving short scales and small sample sizes.
Từ khóa
Tài liệu tham khảo
American Psychological Association., 1999, Standards for educational and psychological testing
Birnbaum, A. (1968). Some latent trait models and their use in inferring an examinee's ability. In F. M. Lord & M. R. Novick (Eds.), Statistical theories of mental test scores (pp. 397-472). Reading, MA : Addison-Wesley.
Camilli, G., 1994, Methods for identifying biased test items
Costa, P.T., Jr., 1989, The NEO-PI/NEO-FFI manual supplement
Holland, P.W., 1993, Differential item functioning
Kim, S.-H., 1995, Applied Psychological Measurement, 8, 291
Lord, F.M., 1980, Applications of item response theory to practical testing problems
Samejima, F., 1969, Psychometrika Monograph Supplement, 34, 100
Smith, P.C., 1969, The measurement of satisfaction in work and retirement
Stark, S., 1999, SGRGEN: A computer program for polytomous data generation [Computer program]
Stark, S., 2000, 3PLGEN: A computer program for dichotomous data generation [Computer program]
Thissen, D., 1991, MULTILOG user's guide (Version 6) [Computer software]
Thissen, D., Steinberg, L. & Wainer, H. (1988). Use of item response theory in the study of group differences in trace lines. In H. Wainer & H. I. Braun (Eds.), Test validity (pp. 147-169). Hillsdale, NJ: Erlbaum.