Eating Disorder-15 (ED-15): Factor structure, psychometric properties, and clinical validation.

ABSTRACT

OBJECTIVE: The purpose of the current study was to explore the factor structure and psychometric properties of the Portuguese version of the Eating Disorder-15 (ED-15), as well as to establish cutoff scores and normative data for the Portuguese version. METHODS: Participants from a nonclinical sample (N = 860) and an eating disorders clinical sample (N = 260) were invited to complete a set of questionnaires, including the Portuguese version of the ED-15. RESULTS: The first-order two-factor structure originally proposed by the ED-15 authors was endorsed through a confirmatory factor analysis (χ2 /df = 2.610; standardized root-mean-square residual = 0.0325; root-mean-square error of approximation = 0.079; Tucker-Lewis index/goodness-of-fit index/incremental fit index > 0.95). Items revealed adequate construct validity (λ = .54-.90; R2  = .29-.81). The ED-15 revealed excellent internal consistency (α = .91) and temporal stability (intraclass correlation coefficient = .92; 95% CI [.84-.95]). Normative data for the ED-15 were provided. The ED-15 demonstrated acceptable concurrent and convergent validity. Receiver operating characteristic analysis revealed that the ED-15 total score accurately discriminates between participants with and without an eating disorder (area under de curve = .80; SE = .017; p ≤ .001; 95% CI [.766-.834]). A cutoff score for clinical significance and a reliable change index were computed. CONCLUSIONS: The Portuguese version of the ED-15 is a reliable and valid measure of eating psychopathology and symptoms, whenever a brief measure is needed, as in session-by-session assessment of therapy progress and outcome.