Simel 1991.

Methods	Randomised controlled trial
Data	Setting: secondary care, USA. 100 patients attending an ambulatory care clinic
Comparisons	Investigated the effect of different consent methods Consent form including a statement that the new treatment may work twice as fast as usual treatment. This was compared to a consent form including a statement that the new treatment may work half as fast as usual treatment
Outcomes	Number consenting (inferred from data rather than being an outcome presented by authors)
Notes
Risk of bias
Item	Authors' judgement	Description
Random Sequence generation ok?	Yes	Randomisation using a computer‐generated scheme
Allocation concealment?	Unclear	Single centre and unclear whether the randomisation list was open or not
Blinding of participants and personnel ok?	Yes	Participants probably were blind but the investigators were not. Investigators got an independent reviewer to look at a portion of interviews, and he/she thought they were fair. They also used a script so less room for investigator initiative.
Blinding of outcome assessment ok?	Yes	See above
Incomplete outcome data handled ok?	Unclear	Adequate
Free of selective reporting?	Yes	Number consenting not presented as an outcome but inferred from data, which is all the review needs
Was the study free of other bias?	Yes	No other biases apparent. Trial was hypothetical but participants were not told this so they thought decision was real
Overall bias?	Unclear	Unclear risk of bias