Challenges in a six-phase process of questionnaire adaptation: findings from the French translation of the Integrated Palliative care Outcome Scale

The Integrated Palliative care Outcome Scale (IPOS) was developed for evaluating essential outcomes for palliative care patients. Our objectives here are to describe the process of a six-phase cross-cultural adaptation of IPOS to French (IPOS-Fr), highlight the difficulties encountered and strategies to solve them, and discuss the implications that adaptation may have on the validity and reliability of a questionnaire. The adaptation of IPOS consisted of six phases: (i) literature review and interviews with target population; (ii) forward translation to French; (iii) backward translation to English; (iv) Expert Review; (v) cognitive interviews with target population; (vi) final review. Translation, cognitive interviews, and exchanges with Expert Review members allowed to make changes adapted to the target language regarding item 5 ("vomiting") and 8 ("sore or dry mouth"), and to identify and address, in the original version of IPOS, syntactic inconsistencies in language used in items 11 to 15 and methodological problems with items 11 ("anxiety about treatment and illness"), 15 ("share … as much as you wanted") and 17 ("problems addressed"). The adaptation also indicated that patients might have difficulties in interpreting items 8 ("sore or dry mouth"), 10 ("poor mobility"), 11 ("anxiety"), 12 (projected feelings of family and friends), and 14 ("feeling at peace"), thus indicating the need of monitoring during the psychometric validation. Following this process, IPOS-Fr has proved content and face validity. In our case, the adaptation allowed adjustments to be made to the questionnaire and, when this was not possible, highlighted potential biases and inconsistencies during the validation. The result relied on an intertwined and iterative process of seeking and reaching semantic, conceptual, and normative equivalence. We are now assessing the psychometrical properties of IPOS-Fr.