Translation and cultural adaptation of the Piper Fatigue Scale for use in Sweden.

The aim of this study was to translate and culturally adapt the revised Piper Fatigue Scale to Swedish. For translation, guidelines for cross-cultural adaptation were used. Two teams independently translated the instrument and two other teams produced back-translations, after which a multidisciplinary committee decided on a Swedish version. In pre-test interviews, ten cancer patients were encouraged to think out loud while completing the Swedish version. Their verbal responses were analysed and used for a second revision. The initial translations varied in words, expressions and grammar, shown in a lack of equivalence to the original instrument after back-translation. In order to establish semantic equivalence, the committee changed some grammatical constructions, and some words were replaced for experiential and conceptual equivalence. When analysing the pre-test, obscurities due to the phrasing of some items were revealed and dealt with in the second revision. This study does not fulfil the process of validation for a translated instrument but offers a sound basis for further accumulation of evidence for validity, and facilitates the choice of an appropriate instrument for studying cancer-related fatigue in Sweden.