Perera 1983.

Methods	Cluster RCT Follow up: providers: DONE patients: NOT CLEAR Blinded assessment: NOT CLEAR Baseline: DONE Reliable outcomes: DONE Protection against contamination: DONE Overall quality: MODERATE
Participants	26 primary care physicians at nine clinics Country: USA Proportion of eligible providers who participated: NOT CLEAR General practice Academic/Teaching setting: NOT CLEAR Type of targeted behaviour: PREVENTIVE CARE (teaching sigmoidoscopy in prevention of cancer) Complexity of targeted behaviour: MEDIUM
Interventions	1. CME: two afternoons with didactic presentation, educational material, discussions and skills training (7 sigmoidoscopies) 2. No intervention control at first, then same as above
Outcomes	Professional practice: rate of sigmoidoscopy per 1000 patients before and after sigmoidoscopy skills preceptorship for both groups Patient: none Seriousness of outcome: MODERATE
Notes	Not analysed as a randomised controlled trial ‐ data not extractable
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear