Factor Structure and Psychometric Properties of the ED-15 in People With an Eating Disorder

Objective: This study examines the factorial structure and psychometric properties of the Eating Disorder-15 questionnaire (ED-15) in a large clinical sample, as well as the instrument's sensitivity to early clinical change in therapy and ability to measure remission. Method: Participants with eating disorders (N = 278) referred to the Flinders University Services for Eating Disorders in South Australia completed the ED-15 as well as other measures of eating disorder symptoms and co-occurring psychopathology, including depression, anxiety, and stress. Results: Confirmatory factor analysis (CFA) revealed a two-factor model for the ED-15. The ED-15 had good internal consistency. It showed satisfactory concurrent validity with moderate correlations with the EDE-Q global score and contribution of unique variance to that score. Correlations indicated good convergent validity with clinical impairment and good divergent validity from depression, anxiety, and stress. The ED-15 showed a significant medium effect size change within the first four sessions of therapy. Good discriminant validity was indicated by cut-off scores used for remission, with significantly different levels of ED psychopathology and other impairments between the two groups. Discussion: This study adds to the four previous psychometric studies of the ED-15, confirming robustness of the English version in a clinical sample. The brevity and psychometric robustness of the ED-15 makes it a preferable measure to the Eating Disorder Examination for sessional assessment of progress in treatment.