Navigating blinding challenges in complex intervention trials: insights from a UK researcher survey

This survey offers insights into the views of experienced UK-based researchers on blinding in complex intervention RCTs. Four key findings emerged: (1) the challenges of blinding due to the inherent complexity of these interventions, (2) the essential role of blinding in reducing bias, (3) the variability in the feasibility of outcome assessment blinding due to practical and resource constraints and (4) the positive impact of stakeholder involvement in addressing blinding challenges. However, respondents expressed dissatisfaction with current quality assessment tools and held divergent views on outcome assessment blinding, highlighting the need for more definitive methodological guidance on blinding in complex intervention trials.