SWAT-1: The effectiveness of a ‘site visit’ intervention on recruitment rates in a multi-centre randomised trial

Table 1 Cochrane Effective Practice and Organisation of Care (EPOC) risk of bias criteria

Risk of bias criterion	Judgement	Reason for judgement
Allocation sequence generation	High risk	Non-randomised method used
Allocation concealment	High risk	Controlled before and after study
Similarity in baseline outcome measurements	High risk	Although all sites had low recruitment prior to the intervention, this was imbalanced across the sites
Similarity in baseline characteristics	Low risk	Similar recruitment processes across sites
Incomplete outcome data addressed	Low risk	No missing data
Knowledge of the allocated intervention	Low risk	Objective outcomes, not affected by knowledge of the intervention
Protection against contamination	Low risk	Allocation was by study site
Free from selective reporting	Low risk	All pre-specified outcomes are reported
Free from other risks of bias	Unclear risk	Possible risk from confounders