Table 5.

An overview of the eight red flags identified in trial managers’ correct predictions of a failure to recruit to target

	Red flag
1	Previous poor performance
2	Slow/non-standard approval process
3	Patient or staff preferences or beliefs
4	Target for recruitment
5	Problems with the trial protocol and/or its implementation
6	Lack of engagement of site team
7	Lack of research experience of site staff/staff changes
8	Busy site staff