Problems translating a questionnaire in a cross-cultural setting.

Questionnaires are widely used in veterinary epidemiological studies. With careful design, assessment and administration, questionnaires can collect accurate data. In cross-cultural settings, questionnaire design is complicated by the added step of translation. As part of a cross-sectional study of smallholder pig raisers in the Philippines, we assessed the importance of translation as a source of error in our questionnaire. The questionnaire contained 120 questions that collected data for entry into 361 separate data-entry fields in a computerised database. The translation was verified using the methods of back-translation and pilot-testing to identify and quantify errors of literal translation, omission and mistranslation. Errors were identified in 44 (37%) questions that obtained data for 147 (41%) data-entry fields. Although errors might have remained in the final translated version of the questionnaire, we have no doubt that the verification procedures substantially improved the internal validity of the questionnaire. It is important that veterinary epidemiologists use such procedures to check the internal validity of translated questionnaires.