Martens 2013.

Methods	Design: RCT Follow‐up: 1, 6 months Attrition: 4%, 6%
Participants	Mean age (years): 20.09 Sex: 65.2% female N participants: 365 Allocation: n = 111 PBSF; n = 121 PNF; n = 133 control Setting: university; higher risk students Country: USA
Interventions	Programme type: motivational interviewing Set‐up: individual single session Key components: The format of the PNF interventions is modelled on the BASICS intervention, and involved the delivery of personalised feedback in an MI‐based framework Duration: 15‐20 min Control: alternative intervention
Outcomes	Outcomes: alcohol consumption were average drinks per week, average number of drinking days per week, and peak blood alcohol concentration (BAC); alcohol‐related problems Measures: modified Daily Drinking Questionnaire; Rutgers Alcohol Problems Index
Funding and Declared Conflicts of Interest	Funded by US NIH. No information or declarations about potential conflicts of interest
Notes	A third trial arm that also comprised an MI‐based intervention has not been included in this review and meta‐analysis; we selected the PNF‐based intervention as this is a more common MI‐oriented intervention
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomised, stratified by sex, via a random number table
Allocation concealment (selection bias)	Unclear risk	Insufficient information to make judgement
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low attrition (6%).
Selective reporting (reporting bias)	Low risk	All alcohol outcomes reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible to blind participants to intervention. Insufficient information to make a judgement about blinding of therapists
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to make judgement
Unit of Analysis issues	Low risk	Not applicable