[Has the translation process impact on the psychometric structure of a questionnaire?]

Little is known about the impact of item translation on the psychometric structure of questionnaires. The analysis of different translation versions within the same language provides an opportunity to address this question. Therefore, in the present study, two of the six available German translations of Eating Disorder Inventory (EDI) were compared with respect to their psychometric structure. A total of 449 female students completed the short forms of the EDI (consisting of the subscales drive for thinness, bulimia and body dissatisfaction). Structural equation modeling revealed that the item contents in both translations had been interpreted equivalently by the participants. In addition, the structural relations among the factors were equivalent across both versions. Whereas invariance of item-pair reliability was not tenable, the distribution of raw scores of the scales was similar. All in all, the findings suggest a very large degree of similarity in the psychometric structure of the alternative translations of the EDI versions. The results are discussed with respect to the lack of standards for the translation of questionnaires.