Brown 2010.

Methods	RCT.
Participants	184 men and women who had been driving while impaired (DWI) with drinking problems, who were recidivists, and who were not currently engaged in DWI interventions. Canada.
Interventions	Brief MI (n= 92) vs. information‐advice (n= 92).
Outcomes	Physiological primary: Biomarkers of alcohol abuse (GGT, AST, ALT, MCV) by blood assay. Non‐physiological primary: Alcohol abuse‐related behaviours (percent risky drinking days) using the MMPI‐Mac Scale. Secondary: Subsequent substance abuse treatment service utilization (data not reported). Readiness to change.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computerized urn randomisation.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding (performance bias and detection bias) Patients and providers	Low risk	"Participants, interviewers who administered the baseline and follow‐up assessments, the statistician who conducted the initial analyses to test the main hypotheses, and investigators were blind to participant assignment."
Blinding (performance bias and detection bias) Assessors	Low risk	"Participants, interviewers who administered the baseline and follow‐up assessments, the statistician who conducted the initial analyses to test the main hypotheses, and investigators were blind to participant assignment."
Incomplete outcome data (attrition bias) All outcomes	Low risk	7% were lost after randomisation and intervention. They were excluded from further analyses (not intention to treat). No reasons for attrition. A further 6% were lost and data were estimated.
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes based on the stated hypotheses.
Other bias	Low risk	Threat of invalidity in self‐report was addressed by corroboration from bio markers and measurement of social desirability in response styles. There were no differences between groups at baseline.