The value of cognitive interviewing techniques in palliative care research

Background: In answering questionnaires, research participants undertake complex cognitive processes, including understanding/interpreting questions, retrieval of information from memory, decision processes to estimate answers and response formulation. Cognitive interviewing techniques are widely used in large surveys, to improve questionnaires by understanding these processes, but their use is less familiar in other areas of palliative research. Aim: This study applied cognitive interviewing techniques, alongside standard piloting, to refine a questionnaire for survey of symptoms in end-stage renal disease patients. Methods: Ten consecutive renal patients were invited to undertake a cognitive interview, while completing a questionnaire comprised of the Memorial Symptom Assessment, Geriatric Depression and Palliative Care Outcomes Scales. Interviews were conducted using 'think-aloud' and concurrent probing techniques, and recorded, transcribed and analysed using content analysis. Results: Nine interviews were completed. A variety of cognitive problems were identified, including legibility/format, comprehension of specific words/phrases, inapplicability of some questions, response estimation and difficulties,caused by combining instruments. These were categorized, using Tourangeau's information processing model, and used to refine the symptom questionnaire. Conclusion: Cognitive interviewing was able to helpfully identify the range and depth of difficulties with questions, to a greater degree than with standard piloting. It may be of particular benefit when instruments are used in different combinations, or applied to new study populations. Wider use of these techniques in palliative research is recommended.