Jennings 2015e.

Methods	Randomised controlled trial
Data	Setting: primary care, UK. Participants were 199 people who were 18 to 80 years with at least 1 component of the metabolic syndrome
Comparisons	Investigated effect of financial incentive on recruitment Intervention: offer of GBP 100 Comparison: no offer
Outcomes	Proportion recruited to trial
Notes
Risk of bias
Item	Authors' judgement	Description
Random Sequence generation ok?	Yes	Done centrally using computer algorithm. There was a slight imbalance in favour of control because of algorithm used but allocation still random
Allocation concealment?	Yes	Done centrally
Blinding of participants and personnel ok?	Yes	Research nurses and staff not blinded but invitations sent out to patients on GP list so staff can not influence response. Participants blinded
Blinding of outcome assessment ok?	Yes	Objective outcome
Incomplete outcome data handled ok?	Yes	Adequate
Free of selective reporting?	Yes	Recruitment data reported, which is all the review needs
Was the study free of other bias?	Yes	No other biases apparent
Overall bias?	No	Low risk of bias