Walitzer 2008.

Methods	RCT.
Participants	169 alcoholic outpatients. USA.
Interventions	(1) a motivational approach to facilitating AA (n=58), (2) a 12‐step directive approach to facilitating AA (n=53), or (3) treatment as usual with no special emphasis on AA (n=58). All conditions received 12 sessions.
Outcomes	Physiological primary: None. Non‐physiological primary: Percentage of days abstinent, percentage of days heavy drinking via the Timeline Followback. Secondary: Attendance at AA meetings.
Notes	On 11 October 2010 we sent an email to Kim Walitzer (walitzer@ria.buffalo.edu) requesting data on retention in treatment.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Random assignment to conditions was conducted by the third author via urn randomisation...".
Allocation concealment (selection bias)	Unclear risk	"Random assignment to conditions was conducted by the third author via urn randomisation...". Insufficient information to permit judgement.
Blinding (performance bias and detection bias) Patients and providers	Unclear risk	Blinding of providers was not possible, but participants could have been blinded.
Blinding (performance bias and detection bias) Assessors	Low risk	"Research interviewers were blind to intervention condition."
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	10% attrition on interview and 15% on questionnaire data. No reasons stated. Similar across conditions. Not ITT in primary analysis.
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes based on the study hypotheses.
Other bias	Low risk	Used collateral interviews to check on self‐report. Differences between groups at baseline were not reported. No additional sources of bias appear to be present.