Fromme 2004 VOLUNTARY.

Methods	Design: RCT Follow‐up: 1, 6 months Attrition: 27% at 1 month and 51% at 6 month
Participants	Mean age (years): 19.26 Sex: 59% male N participants: 452 Allocation: not reported, though n = 285 intervention and n = 118 controls were included in the analysis Setting: university, all risk levels Country: USA
Interventions	Programme type: Lifestyle Management Class (LMC) with brief motivational interviewing components Set‐up: 1 individual session Key components: change in drinking, negative consequences of intoxication, driving after drinking, and motivation for making behavioural changes Duration: 75 min Control: assessment only
Outcomes	Outcomes: typical weekly drinking; monitored weekly drinking; heavy drinking composite, DUI composite; past month negative consequences Measures: University of Rhode Island Change Assessment; Daily Drinking Questionnaire; Positive and Negative Consequences Experienced Questionnaire; Drinking after Driving question, Past week monitorisation alcohol card; adherence and quality of the LMC co‐leaders
Funding and Declared Conflicts of Interest	Research Supported by the National Institute on Alcohol Abuse and Alcoholism. No information or declarations about potential conflicts of interest
Notes	Results combined for professional and peer‐led intervention groups as there were no differences between these groups. Results reported separately for mandated and voluntary groups. Only 1 month outcomes reported and included in MA
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information to make a judgement
Allocation concealment (selection bias)	Unclear risk	Insufficient information to make a judgement
Incomplete outcome data (attrition bias) All outcomes	High risk	High attrition (27%); missing cases analyses used
Selective reporting (reporting bias)	Low risk	All expected outcomes reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible to blind participants to intervention
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to make a judgement
Unit of Analysis issues	Low risk	Not applicable