Item Response Theory (IRT) methodologies were employed in order to examine the Myers-Briggs Type Indicator (MBTI) for differential item functioning (DIF) on the basis of crossed gender and ethnicity variables. White males were the reference group, and the focal groups were: black females, black males, and white females. The MBTI was predicted to show DIF in all comparisons. In particular, DIF on the Thinking-Feeling scale was hypothesized especially in the comparisons between white males and black females and between white males and white females. A sample of 10,775 managers who took the MBTI at assessment centers provided the data for the present experiment. The Mantel-Haenszel procedure and an IRT-based area technique were the methods of DIF-detection.

Results showed several biased items on all scales for all comparisons. Ethnicitybased bias was seen in the white male vs. black female and white male vs. black male comparisons. Gender-based bias was seen particularly in the white male vs. white female comparisons. Consequently, the Thinking-Feeling showed the least DIF of all scales across comparisons, and only one of the items differentially scored by gender was found to be biased. Findings indicate that the gender-based differential scoring system is not defensible in managerial samples, and there is a need for further research into the study of differential item functioning with regards to ethnicity.