Gender-based differential item functioning in measures of eating pathology

Objective: Eating disorder (ED) symptoms are common and impairing in males, despite their perception as “female” disorders. As existing self-report symptom measures were developed and primarily validated in women, there is a need to establish the utility of these measures in men. The present study used differential item functioning (DIF) analyses to explore whether item endorsement differed by gender for three commonly used ED symptom measures. Method: Participants were undergraduate men (n = 1,083) and women (n = 2,424) from three universities in the United States. Global scores on the Eating Attitudes Test-26 (EAT-26), Eating Disorder Examination Questionnaire (EDEQ), and Eating Disorder Diagnostic Scale for DSM-IV (EDDS) were examined. Tests of DIF were conducted by regressing each item against its composite scale score, and then comparing fit and variance explained (R²) to a model with the interaction of item*gender. The clinical significance threshold for DIF is ΔR² ≥ 0.13. Results: There was no evidence of clinically significant DIF within the EAT-26, EDEQ, or EDDS. Discussion: Findings suggest that the examined measures perform similarly for undergraduate men and women, supporting their use in nonclinical male samples. However, development and testing of items reflecting ED symptoms that more commonly occur in males (e.g., muscularity-oriented behaviors) is encouraged.