Acceptance: what's in a name? A content analysis of acceptance instruments in individuals with chronic pain.

UNLABELLED: Instruments to assess chronic pain acceptance have been developed and used. However, whether and to what extent the content of the items reflects acceptance remain uninvestigated. A content analysis of 13 instruments that aim to measure acceptance of chronic pain was performed. A coding scheme was used that consisted of 3 categories representing the key components of acceptance, that is, disengagement from pain control, pain willingness, and engagement in activities other than pain control. The coding scheme consisted of 5 additional categories in order to code items that do not represent acceptance, that is, controlling pain, pain costs, pain benefits, unclear, and no fit. Two coders rated to what extent the items of acceptance instruments belonged to one or more of these categories. Results indicated that acceptance categories were not equally represented in the acceptance instruments. Of note, some instruments had many items in the category controlling pain. Further analyses revealed that the meaning of acceptance differs among different instruments and among different versions of the same instrument. This study illustrates the importance of content validity when developing and evaluating self-report instruments. PERSPECTIVE: This article investigated the content validity of questionnaires designed to measure acceptance in individuals with chronic pain. Knowledge about the content of the instruments will provide further insight into the features of acceptance and how to measure them.