Bull 2012.

Methods	Cluster randomised study over 6 months Conducted between 2010 and 2011
Participants	1578 males and females based in the USA Age: 16–25 years
Interventions	Intervention group: availability of a Facebook page with sexual health content Control group: access to a tailored Facebook news page
Outcomes	Primary outcomes Improved adherence: condom use at last sexual intercourse Improved adherence: proportion of sex acts protected by condoms in the past 60 days Secondary outcomes Change in attitude/knowledge: intention to use condoms at the next sexual encounter self‐efficacy of condom usage
Notes	Inclusion criteria fulfilled through use of interactive website with appropriate outcome measures.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described in sufficient detail.
Allocation concealment (selection bias)	Unclear risk	Not described in sufficient detail.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described in sufficient detail.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described in sufficient detail.
Incomplete outcome data (attrition bias) All outcomes	High risk	High attrition with 41% of controls and 55% of intervention participants.
Selective reporting (reporting bias)	Low risk	All outcomes reported.
Other bias	Unclear risk	Misclassification and social desirability bias. Selection bias through recruitment methods. Contamination bias.