Analysis of the Gender Variable in the Eysenck Personality Questionnaire–Revised Scales Using Differential Item Functioning Techniques

Studies in the field of personality have systematically found gender differences in two of the three dimensions of the Eysenck model: neuroticism and psychoticism. This study aims to analyze these differences in the Eysenck Personality Questionnaire—Revised (EPQ-R) scales using differential item functioning (DIF) techniques to determine whether these differences are the result of a differential functioning of the items between males and females or if, on the contrary, they may be reflecting true differences in the assessed dimensions. To this end, 794 participants within a wide age range were evaluated using the EPQ-R test. The following detection methods were used in order to examine DIF: standardization, the simultaneous item bias test, logistic regression, Lord's χ2 test, and the differential functioning of items and tests framework. According to the results, the gender differences observed do not seem to be the result of any flaw of the measuring instrument used.