Mixed-Methods Evidence Synthesis

The strength of quantitative evidence will be assessed using GRADE, and confidence in qualitative findings will be assessed using CERQual. Quantitative and qualitative data will be analyzed independently and then merged to generate an integrated understanding. Qualitative findings will be structured using the theoretical framework of acceptability, which has seven domains: affective attitude, burden, ethicality, intervention coherence, opportunity costs, perceived effectiveness, and self-efficacy. The review applies both the theoretical domains framework and the theoretical framework of acceptability to understand behavioural mechanisms and acceptability factors. Qualitative findings will be deductively mapped to the theoretical domains framework to identify behavioural determinants influencing FIT uptake and return. The convergent mixed-methods approach is intended to show not only whether interventions work but also why they work, for whom, and under which circumstances.