Employing cognitive interviewing to evaluate, improve and validate items for measuring the health-related quality of life of women diagnosed with ovarian cancer

Background Use of patient-reported outcome measures in clinical settings facilitate the delivery of better health care to improve patient health outcomes. Previously collected qualitative data indicated themes that could inform items for a health-related quality of life measure. This study investigated the content validity of items for inclusion in a new health-related quality of life measure suitable for patients with ovarian cancer. Methods Cognitive interviewing techniques were used with fourteen women diagnosed with ovarian cancer and at different times since diagnosis, to evaluate items derived from the previously collected qualitative dataset. A set of draft items was administered via telephone, Zoom and WhatsApp app together with questions on item meaning and wording. Interviews were transcribed and thematically analysed. Results Four broad themes emerged in relation to the questionnaire construction and comprehension of items: intent and clarity, wording, relevance and context, and overall questionnaire construct. All draft items were adjusted based on the interview findings. A final set of 38 health-related quality of life items comprised 7 items describing physical health and functioning, 21 describing emotional wellbeing and 10 items describing social wellbeing; each rated on a five-point frequency response scale. Conclusion The items reflected a range of personal experiences associated with the patient clinical journey, creating a health-related quality of life tool specific to women diagnosed with ovarian cancer. The cognitive interviewing process established content validity for the tool, thereby, preparing it for field testing and evaluation of its psychometric properties. This study highlighted the fundamental role of cognitive interviewing during health-related quality of life questionnaire development to ensure that item content is grounded in patient feelings, functioning and meaning.