Assessing Differential Step Functioning in Polytomous Items Using a Common Odds Ratio Estimator

Abstract

Many statistics used in the assessment of differential item functioning (DIF) in polytomous items yield a single item‐level index of measurement invariance that collapses information across all response options of the polytomous item. Utilizing a single item‐level index of DIF can, however, be misleading if the magnitude or direction of the DIF changes across the steps underlying the polytomous response process. A more comprehensive approach to examining measurement invariance in polytomous item formats is to examine invariance at the level of each step of the polytomous item, a framework described in this article as differential step functioning (DSF). This article proposes a nonparametric DSF estimator that is based on the Mantel‐Haenszel common odds ratio estimator( Mantel & Haenszel, 1959 ),which is frequently implemented in the detection of DIF in dichotomous items. A simulation study demonstrated that when the level of DSF varied in magnitude or sign across the steps underlying the polytomous response options, the DSF‐based approach typically provided a more powerful and accurate test of measurement invariance than did corresponding item‐level DIF estimators.

Cite this work

No public copy is stored for this record, so only the metadata is cited.

Stored only when both papers are in the corpus — 54 citations exist upstream.

Papers that cite the same references — the relational fallback while embeddings are still backfilling.