Added value of qualitative studies in the development of health related patient reported outcomes such as the pain coping and cognition list in patients with sub-acute neck pain

Psychometric analyses, such as factor analysis, internal consistency and construct validity analysis, are well known and frequently applied methods in the development of health related patient reported outcomes. These statistical indexes shed very little light on how respondents interpret individual items, or on the meaning of their responses. In this study, the Pain Coping and Cognition List (PCCL), a quantitatively validated psychological questionnaire developed to assess chronic pain, has been subjected to a qualitative research method: the Three Step Test Interview (TSTI), an observational technique that aims to identify problems with self reported questionnaires. It consists of three phases: 1) concurrent thinking aloud; 2) a retrospective interview; 3) a semi-structured interview. Participants with sub-acute neck pain distinguished six different types of problems: long complicated formulations, composite questions, irrelevant questions, lacking frame of reference, problematic words, and wrongly interpreted questions. This study illustrates that qualitative methods have an added value when developing self-report questionnaires because some of the problems that were highlighted that cannot be identified using quantitative methods only. Therefore, we recommend that a full qualitative study should be an integral part of the development of questionnaires. The TSTI method is very useful for this purpose.