Methods	Cluster RCT, with the hospital as the unit of randomisation.
Participants	37 hospitals. 2938 patients.Intervention:n=20 and Control: n=16 Country: US Type of targeted behaviour: general management of a problem myocardial infarction)
Interventions	Intervention Local Opinion Leaders + distribution of educational materials. Method of OL identification: Sociometric Proportion of social network that nominated OL: 38% Single OL or OL teams identified: one single OL per hospital OL disseminated information: Informal & Formal (conferences, clinical practice guide-lines, audit & feedback) t:nc="2"OL frequency of involvement:UNCLEAR Control Audit & feedback
Outcomes	Eligible patients receiving drugs for treatment of acute myocardial infarction
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	P.1369/ “..hospitals were stratified and randomised by size from within each of the nine strata to experimental or control condition (standard care)
Allocation concealment (selection bias)	Low risk	it was a cluster RCT, with the hospitals as the unit of randomisation
Blinding (performance bias and detection bias) All outcomes	Low risk	P.1359/ Col 2/ Para 2 Hospital administrators, physicians, AMI patients and nurse abstractors were all blinded with respect to study hypothesis and experimental assignment at each hospital
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	Pg. 1361/Col 2/Para1 There were no significant differences in baseline rates of use of study drugs between experimental and control hospitals Pg 1362/Table 2
Similar baseline characteristics?	Low risk	PG.1361/Col 1/Para 3 “Table 1 presents demographic and clinical characteristics of experimental and control patients before and after the intervention. Both groups were comparable overall and with respect to several characteristics that predicted use of study drugs at baseline, namely old age.(>75 years), female sex; severe co-morbidity, recent symptom-onset (6 hours) and heart failure Pg.1361/Col 3/Table 1
Protection against contamination?	Low risk	Pg. 1359/Col 1/Para 3 To minimise contamination of control hospitals, large cities (i.e. St. Paul-7 hospitals and 2536 patients) and Minneapolis (11 hospitals and 2536) were randomised as clusters, resulting in a state-wide sample of 20 experimental and 17 control hospitals