Intervention description is not enough: evidence from an in-depth multiple case study on the untold role and impact of context in randomised controlled trials of seven complex interventions

Table 4 Summary of data collection

	Number and nature of participants/documents	Total number of data sources (interviews, focus groups and documents)
Phase 1: Single exploratory case
Interviews	Thirteen longitudinal interviews with four breast care nurses:	15
	Three interviewed three times.
	One interviewed four times.
	Plus: one interview with a research nurse
	And one interview with a charge nurse
Documents	Protocol, ethics application, monitoring reports x 2, final report, Minutes of meetings x 15, field notes of PI and researcher	22
Phase 2: Multiple explanatory case study
Interviews	Seven principal investigators and one research assistant	8
Documents	Seven trial protocols/proposals	30
	Six ethics forms
	Five monitoring reports
	Seven final reports
	Five published papers
Focus	One group with three research nurses	9
groups	One group with two nurse members of the ethics committee
	One group with four PIs
Total		84

ISSN: 1745-6215