Differential item functioning between different forms of test booklets
Koniewski, Maciej ; Majkut, Przemysław ; Skórska, Paulina
Educational Research Institute
Differential item functioning (DIF) between different forms of test booklets was analysed. Both test forms shared the same items and only the sequence of options for the multiple choice items differed. Analysis was performed on 2013 data from two forms, A and B of “The history and civic studies” test administered in lower secondary schools in the Lubelskie, Malopolskie and Podkarpackie Voivodeships (n = 81 545). To detect DIF, the Mantel–Haenshel test, logistic regression and standardisation were used. Methods for DIF visualisation were demonstrated. Results indicated meaningful differences in item functioning between test forms, especially with a repeat letter pattern of answer keys on items bundled in testlet when correctly answered, e.g. A, A, A. Such a pattern is named an ‘anti-pattern’, because test takers may consider such a response pattern unlikely and in consequence answer incorrectly. Findings from this study should provide important guidelines for test development.
psychometry ; differential item functioning ; DIF ; standardization ; Mantel–Haenszel test ; logistic regression