Winters 2007.

Methods	RCT.
Participants	Students (n = 53) identified in a school setting as drug abusers. USA.
Interventions	2 sessions of MI with the adolescent only (n=26) vs assessment only control (n=27).
Outcomes	Physiological primary: None. Non‐physiological primary: Number of alcohol use days, number of binge days, number of illicit drug use days. Secondary: Additional treatment. Follow‐up at 6 months.
Notes	There was also a third group that received 2 sessions with the adolescent and one with the parent (n=26). This group did not meet our inclusion criteria. 1 student in the control group dropped out, so each group in the analyses contain 26 students.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"...randomly assigned..."
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement.
Blinding (performance bias and detection bias) Patients and providers	High risk	No blinding.
Blinding (performance bias and detection bias) Assessors	Low risk	"An experienced research assistant, who was blind to treatment condition, completed the intake, 1‐month, and 6‐months follow‐up interviews."
Incomplete outcome data (attrition bias) All outcomes	Low risk	1% attrition at 6 months follow‐up.
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes based on the study hypotheses.
Other bias	High risk	"During the 6‐months TSR interview, those in the BI–AP condition reported more additional treatment (27%) compared with those in the BI–A condition (16%)". Only self‐report. There were no differences between groups at baseline.