Translation and Evaluation of the Reliability and Validity of Eating Disorder Inventory -3 Questionnaire Among Iranian University Students

Background Eating disorder inventory (EDI) is a self-reported questionnaire which has been used widely for the assessment of symptoms in clinical samples and research. Objectives In the current study we sought to evaluate the validity and reliability of the Persian form of the 3rd variant of EDI (EDI-3) questionnaire. Methods 452 individuals (299 women and 153 men) completed the EDI-3 questionnaire. The translation and back-translation procedure was adopted to provide the Iranian form of the questionnaire. A voluntary response sample of university students among different departments completed the survey in Tehran, Iran. Psychometric aspects of the instrument such as reliability (test-retest analysis and internal consistency), validity (a comparison of known groups) and item correlation with their speculated domain were evaluated. Results The mean age of participants was 22.31 ± 3.30 and 22.43 ± 4.41 in men and women group respectively. Generally, the questionnaire demonstrated satisfactory reliability and all domains yield the minimal reliability standards (intra- class correlation and Cronbach’s alpha > 0.6), unless asceticism and interpersonal alienation in both women and men (Cronbach’s alpha for two items in both groups were < 0.4). Correlation matrix also demonstrated satisfactory results in all territories except asceticism and interpersonal alienation. The content validity for both clarity and relevancy indices was 0.8 or higher (for 87 out of 91 questions). Conclusions The current study has yielded some introductory proof of the reliability and validity of the EDI-3 to be applied in Iran, albeit additional research is needed to carry out discriminant or convergent (concurrent) validation procedures in eating disorder patients.