Mastroleo 2010.

Methods	RCT.
Participants	122 US heavy drinking college students.
Interventions	1. peer counselled MI with supervision (n= 74) 2. peer counselled MI without supervision (n= 82) 3. no treatment control (n= 82).
Outcomes	Daily Drinking Questionnaire (total drinks per week, peak BAC, heavy drinking behaviours).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No mention of allocation method.
Allocation concealment (selection bias)	Unclear risk	No mention of allocation concealment.
Blinding (performance bias and detection bias) Patients and providers	High risk	Patient and providers were not blinded to treatment allocation.
Blinding (performance bias and detection bias) Assessors	Unclear risk	It is not stated whether assessors were blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	16% attrition at 3 months. Balanced. No reasons stated. ITT (imputed missing data).
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes based on the study purposes.
Other bias	Unclear risk	Only self‐reported outcomes. 61/156 (39%) of randomised participants did not receive the intervention. Differences between groups at baseline were not reported.