Generalized Mantel–Haenszel Estimators for Simultaneous Differential Item Functioning Tests

Abstract

The Mantel–Haenszel estimator is one of the most popular techniques for measuring differential item functioning (DIF). A generalization of this estimator is applied to the context of DIF to compare items by taking the covariance of odds ratio estimators between dependent items into account. Unlike the Item Response Theory, the method does not rely on the local item independence assumption which is likely to be violated when one item provides clues about the answer of another item. Furthermore, we use these (co)variance estimators to construct a hypothesis test to assess DIF for multiple items simultaneously. A simulation study is presented to assess the performance of several tests. Finally, the use of these DIF tests is illustrated via application to two real data sets.

The Net Promoter Score interrogated through a services marketing lens: Review and recommendations for service organizations

“…As a single item scale, it is usually exempt from traditional multi-group measurement invariance testing. However, service organizations could explore techniques such as Differential Item Functioning (DIF) (Liu et al, 2023). This might be particularly useful for multinational service organizations, which employ NPS in different markets.…”