Llewellyn‐Thomas 1995b.

Methods	Randomised controlled trial
Data	Setting: secondary care, Canada. 100 patients attending the outpatient department of a cancer hospital
Comparisons	Investigated the effect of different trial information methods Searchable computerised information on a hypothetical trial, including purpose, description of treatment group and randomisation, possible benefits, side effects and patients' rights. This was compared to tape‐recorded information on a hypothetical trial, including purpose, description of treatment arm and randomisation, possible benefits, side effects and patients' rights
Outcomes	Proportion recruited to hypothetical trial
Notes
Risk of bias
Item	Authors' judgement	Description
Random Sequence generation ok?	Unclear	Just says framing was randomly determined
Allocation concealment?	Unclear	Used sealed envelopes although doesn't mention numbering
Blinding of participants and personnel ok?	Yes	Unclear if the interviewer or the participants were blinded. It depends on what the participants were told. Interviewer did not seem to do more than help with equipment, so perhaps limited room for bias
Blinding of outcome assessment ok?	Yes	Somewhat unclear (see above), subjective outcome but probably did not affect outcome
Incomplete outcome data handled ok?	Yes	Adequate
Free of selective reporting?	Yes	Willingness to take part outcome presented, which is all the review needs
Was the study free of other bias?	No	Hypothetical trial
Overall bias?	Yes	High risk of bias