Mean Comparisons of Many Groups in the Presence of DIF: An Evaluation of Linking and Concurrent Scaling Approaches

One of the primary goals international large-scale assessments in education is comparison country means student achievement. This article introduces a framework for discussing differential item functioning (DIF) such mean comparisons. We compare three different linking methods: concurrent scaling based on full invariance, partial invariance using RMSD statistic, and robust nonrobust approaches separate scaling. Furthermore, we analytically derive bias methods presence DIF. In simulation study, show that provide less biased than approach case items.