A Multidimensionality-Based DIF Analysis Paradigm

Abstract

A multidimensionality-based differential item func tioning (DIF) analysis paradigm is presented that unifies the substantive and statistical DIF analysis approaches by linking both to a theoretically sound and mathematically rigorous multidimensional conceptualization of DIF. This paradigm has the potential (1) to improve under standing of the causes of DIF by formulating and testing substantive dimensionality-based DIF hypotheses; (2) to reduce Type 1 error through a better understanding of the possible multidimensionality of an appropriate matching criterion; and (3) to increase power through the testing of bundles of items measuring similar dimen sions. Using this approach, DIF analysis is shown to have the potential for greater integration in the overall test development process.