A multidimensionality-based DIF analysis paradigm

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. Index terms: bias, bundl