An introduction to Differential Item Functioning (original) (raw)

Differential Item Functioning (DIF) has been increasingly applied in fairness studies in psychometric circles. Judicious application of this methodology by the researchers, however, requires an understanding of the technical complexities involved. This has become an impediment in the way of specially non-mathematically oriented researches. This paper is an attempt to bridge the gap. It provides a non-technical introduction to the fundamental concepts involved in DIF analysis. In addition, an introductory level explanation of a number of the most frequently applied DIF detection techniques will be offered. These include Logistic Regression, Mantel-Haenszel, Standardization, Item Response Theory, and the Rasch model. For each method, a number of the relevant software are also introduced.