Guidelines for the Translation of Questionnaires

Stephan Weiland
Richard Beasley
David Strachan

ISAAC Phase One Coordinating Committee

ISAAC Document 054


The following steps are recommended for the translation of questionnaires:

  1. The questionnaires are translated by one or more persons who are bilingual and familiar with the area in which the questionnaire will be used.

  2. In order to find the most appropriate translation for difficult terms, e.g.: "wheezing" or "whistling in the chest", it is proposed to:

    1. Ask local doctors about local words to describe these terms.

    2. Ask children with asthma and parents of children with asthma how they would describe the breathing during an asthma episode.

    3. Show the video and ask children with asthma and parents of children with asthma how they would describe the breathing of the children and adolescents in the video.

    4. Submit a list of possible descriptors to children with asthma and parents of children with asthma and ask them to indicate, e.g.: using a rating system, which description(s) they favour best.

  3. The most appropriate translation should be agreed upon among a group of national experts on the basis of 2a - 2d. The national questionnaires should allow for differences in the wording of questions according to the local use of language.

  4. The questionnaires should be translated back into English by an independent translator. Modifications should be made if necessary.

  5. The questionnaires should be tested in populations representative of the study populations. Modifications should be made if necessary.

  6. Steps 2 to 5 are repeated if necessary.

A list of languages the questionnare has already been translated to can be found at Resources > Tools/translations and in the Phase Three manual.


The translation of questionnaires is a key issue for the validity of comparisons involving non-English speaking countries. It is recognised however, that the Steps 2c and 2d may be too costly for some countries or centres and that those countries or centres may decide to leave them out. The translated questionnaires must have the same structure and logic as the original. In addition, we draw the attention to the need that the translations must be understood by the children and parents themselves and experience from Germany shows that it may well differ from the terminology of medical professionals [1].

  1. Weiland SK, Kugler J, von Mutius E, Schmitz N, Fritzsch C, Wahn U, Keil U. The language of pediatric asthma patients: A study of symptom description. Monatsschrift Kinderheilkunde 1993; 141(11): 878-82 [in German].