Table 2

Summary of included quantitative studies

	Study type	RCT recruiting to	Overview (country, aim)
Donovan et al (2003)23	RCT	ProtecT Trial, prostate cancer treatment	UK To investigate the comparative effectiveness of nurses and surgeons in recruiting patients.
Monaghan et al (2007)24	RCT	ADVANCE trial (diabetes)	Australia Investigation of the effect of extra communication from central trial coordinators on recruitment.
Lienard et al (2006)25	RCT	Adjuvant treatment of breast cancer	France To assess the impact of on-site initiation monitoring visits on patient recruitment.
Fletcher et al (2010)26	Observational time series	Primary care-based multicentre RCT, stroke trial	UK To examine whether changes to the design and conduct of a primary care-based RCT were associated with changes in patient recruitment.
Donovan et al (2002)27	Observational time series	ProtecT trial—treatment for prostate cancer	UK Feasibility study for main trial Qualitative research used to address barriers to recruitment and make changes to protocol.
Donovan et al (2009)28	Before and after study	ProtecT trial—treatment for prostate cancer	UK Main trial results A complex intervention was designed using qualitative methods to improve recruitment (ie, regular training of recruiting staff, centre reviews if centre not recruiting to target, documents to provide advice and personal feedback).
Kenyon et al (2005)29	Before and after study	ORACLE trial—double-blind RCT antibiotic treatment for women in idiopathic preterm labour	UK Trial was not recruiting successfully so changes were made (introduction of lead midwife responsible for recruitment with protected time for research).
Submacular Surgery Trials Research Group (2004)30	Case study (with comparison group)	SST—submacular surgery trial	USA Comparison of university- and community-based practices taking part in three multicentre randomised trials. One outcome measure was patient accrual.

RCT, randomised controlled trials.