Table 1 Interview topic guides

Chief Investigator

The trial: History of the trial, details of the trial, current stage, successes, current and anticipated challenges

TSC Chair

The TSC: Frequency of meetings, composition of TSC, reasons for selecting members, how Chair was selected and role in meetings, nature of the group’s decision-making and members’ involvement, examples of actioned group recommendations, impact of TSC, communication between TSC and TMG, relationship of and communication between TSC and other trial oversight committees, aspects of TSC that could be improved, recommendations for other trials regarding role of TSC

TSC members

The trial: History of participation in the TSC, views regarding composition of the group and frequency of meetings, relationships with other members, value of TSC meetings, TSC’s role in decisions regarding trial, relationship of and communication between TSC, TMG and other trial oversight committees

TSC meetings: Meeting organisation, Chair and leadership of meeting, communication during meeting, process of decision-making (positive aspects and challenges/difficulties, own and others’ contributions to decision-making), process of agreeing and assigning actions, communication of actions to other groups/trial personnel, how future TSC meetings could be improved

Trial funder representatives

Funders’ expectations and views of TSCs, process of selecting TSC, examples of TSC working well, examples where TSCs haven’t worked well, different models of TSCs, role of TSC Chair, role of Patient and Public Involvement (PPI), role of the trial funder, regulatory bodies, recommendations regarding TSCs

Sponsor representatives

Sponsors’ expectations and views of TSCs, role of sponsor in trial, responsibilities of sponsor, relationship between sponsor, TSC and funder, challenges faced by trials, qualities of a TSC Chair, decision-making by a TSC, value of TSCs