2.2.1. Qualitative Data Collection
In our qualitative study, we organized a focus group that took place over two sessions (one in Phase 1 and the other in Phase 2), each lasting 90 min, involving the same seven (7) participants (3 men and 4 women). We had open conversations with all seven individuals, led by the principal investigator, using a structured interview guide to understand their smartphone usage, experiences with health apps, familiarity with clinical trials, recommend features needed to design a clinical trial digital app, and factors that influence their willingness to participate in a clinical trial (see 