Methods	Cluster RCT, the community was the unit of randomisation
Participants	Primary care practitioners from 6 community hospitals. 114 inpatients and 472 outpatients. (Intervention: n=3 and Control: n=3) Country: US Type of targeted behaviour: general management of a problem (osteoarthritis care)
Interventions	Intervention Local Opinion Leaders Method of OL identification: Sociometric Proportion of social network that nominated OL: NOT CLEAR Single OL or OL teams identified:one single OL OL disseminated information: NOT CLEAR OL frequency of involvement:UNCLEAR Control Standard dissemination
Outcomes	Proportion of patients with osteoarthritis receiving appropriate care for 6 treatment variables and for 3 total hip arthroplasty variables
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	P.109/Col 1?para 1 Letters were sent to all communities with these characteristics, and 6 communities agreed to participate. Three were randomly selected to be controls, while the other three were desigated as intervention communities
Allocation concealment (selection bias)	Low risk	It was a cluster RCT, with the community as the unit of randomisation
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not mentioned in the paper
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not mentioned in the paper
Selective reporting (reporting bias)	Low risk	All outcomes mentioned in the methods section were also presented in the results
Other bias	Low risk
Similar baseline outcome measures?	Low risk	P.110/Col 1/Table 1
Similar baseline characteristics?	Low risk	P.109/Col 1
Protection against contamination?	Low risk	The community was the unit of allocation.