Systematic, contextual, and individual influences drive trialists' behaviour relating to greener trial design and...

To identify the key behavioural determinants that influence how people working in clinical trials ('trialists') design and deliver greener trials.

We conducted semi-structured focus groups and interviews with trialists involved in the design and conduct of clinical trials in the UK. Participants were recruited from a preceding survey, supplemented by purposive sampling through established trial networks and professional groups. Data collection was guided by the Theoretical Domains Framework (TDF) where analysis combined deductive TDF coding with inductive thematic development.

Three focus groups and nine interviews with a total of 23 participants including diverse roles, such as Clinical Trials Unit (CTU) directors, trial managers, statisticians, Quality Assurance staff, and researchers, were conducted. We identified 34 belief statements across all 14 TDF domains which were synthesised into five overarching themes: 1. Developing and promoting a culture for greener trials; 2. Weighing up the anticipated benefits against the unknowns; 3. Tensions between intrinsic and extrinsic priorities; 4. Degree of control over the enablement of greener trials; and 5. Negotiating gaps to address individual uncertainties. The study found that trialists' actions were shaped by a range of behavioural mechanisms. Cultural and contextual constraints, competing priorities, and limited organisational support were key challenges; while leadership, funders' expectations, and existing sustainability practices were identified as potential opportunities.

This study provides an in-depth theory-informed behavioural analysis of the challenges and opportunities for making clinical trials greener. These findings provide a basis for designing behaviour change strategies to support trialists' adoption of greener trials.