Influence of DIF on differences in performance of Italian and Asian individuals on a reading comprehension test of Spanish as a foreign language (negative emotionality) in Hong Kong.

Research into Differential Item Functioning (DIF) has been an active research area in language testing (Ferne and Rupp, 2007). In this study we analyzed the DIF of two groups with different types of native language (927 Italians and 280 Asians) in a reading comprehension task forming part of an exam in Spanish as a foreign language. The Mantel-Haenszel (MH) and Rasch procedures for the detection of uniform and nonuniform DIF were used. The results reveal that the Rasch model and MH converge substantially on the results. Uniform DIF was detected in 6.6 per cent of the items and nonuniform DIF in 16.7 per cent. Half of the items affected by DIF favored the focal group (Asians) and the other half favored the reference group (Italians). The difference in test performance of the two groups did not appear to be affected by the elimination of items with DIF.