Bell 2007.

Methods	RCT.
Participants	60 veterans enrolled in substance abuse treatment at the New Mexico Veterans Affairs Health Care System, USA.
Interventions	MI + TAU (n=40) vs TAU (n=20).
Outcomes	Physiological primary: None. Non‐physiological primary: Drinks per day, number of drinking days, percent within safe drinking limits, substance use per day, and number of substance use days. Secondary: None. Follow‐up was at 2 months.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Participants were assigned to condition by a computerized urn randomisation program which balanced for distribution to the groups by the following factors: age, education, presence or absence of history of head injury with loss of consciousness, gender, and enrolment (yes/no) in the six standard treatments..."
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	Unclear risk	It is not stated whether assessors were blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	22% were lost to follow‐up at 2 months. Not ITT. Reasons for loss to follow‐up stated, but reasons for removal were that they were disqualified because of lack of baseline drinking (n=7). Loss was balanced.
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes based on the stated hypotheses.
Other bias	High risk	Only self‐reported outcomes. More females received MI.