| Abstract: | Investigations of differential distractor functioning (DDF) can provide valuable information concerning the location and possible causes of measurement invariance within a multiple‐choice item. In this article, I propose an odds ratio estimator of the DDF effect as modeled under the nominal response model. In addition, I propose a simultaneous distractor‐level (SDL) test of invariance based on the results of the distractor‐level tests of DDF. The results of a simulation study indicated that the DDF effect estimator maintained good statistical properties under a variety of conditions, and the SDL test displayed substantially higher power than the traditional Mantel‐Haenszel test of no DIF when the DDF effect varied in magnitude and/or size across the distractors. |
