White 2006.

Methods	RCT.
Participants	222 mandated college students. USA.
Interventions	Brief motivational interview (n = 180) vs written feedback only (n = 168).
Outcomes	Physiological primary: None. Non‐physiological primary: Past month alcohol frequency, number of occasions of heavy episodic drinking, number of drinks and number of hours of drinking each day in a typical week in the last month. Frequency of marijuana use in the past month. Secondary: None. Follow‐up at 3 months post‐intervention.
Notes	White 2007 is the same study with further recruitment (n=348). The follow‐ups were at 4 and 15 months.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomly assigned by the flip of a coin.
Allocation concealment (selection bias)	Low risk	Randomly assigned by the flip of a coin.
Blinding (performance bias and detection bias) Patients and providers	High risk	No blinding.
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	5% lost to follow‐up. Reasons not stated. Balanced. ITT not conducted.
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes based on the study hypotheses.
Other bias	High risk	Only self‐report but included the Social Desirability Scale. Participants in the BMI group were in an earlier college year and had higher RAPI scores than participants in the written feedback group at baseline.