2.3.2. Cognitive debriefing

The second part of the interview assessed patients’ understanding of the PGI-S and PGI-C scales. The PGI-S asked patients to report the overall severity of their cancer symptoms over the past 7 days using a five-point Likert scale with the response options “no symptoms,” “mild,” “moderate,” “severe,” and “very severe.” Changes in patients’ cancer symptoms were reported via the PGI-C, where patients were asked about their current symptoms compared with their experience 6–12 months before the interview. Change was reported via a five-point Likert scale with the response options “much better,” “a little better,” “no change,” “a little worse,” and “much worse.” The PGI-S and PGI-C items were shared with patients through an online screen-sharing program, and patients were asked to respond to the questions based on the symptoms reported in the concept elicitation part of the interview. Patient understanding of these measures was assessed through a cognitive debriefing interview, which included questions focused on the clarity and understandability of the PGI-S and PGI-C; relevance to patients’ experience with NSCLC; and the clarity, understandability, and appropriateness of response options.