Davis 1986

Methods	Setting: cessation clinic, USA Recruitment: community volunteers Group size: 3 to 8
Participants	45 smokers who completed treatment Therapists: 9 advanced clinical psychology graduate students with no previous experience. Each conducted one group
Interventions	All conditions received 6 × 1½ to 2 hour weekly meetings based on Pomerleau and Pomerleau broad‐spectrum cessation package. TQD week 5 1. 'Experimental' condition added active cognitive behavioral skills training focusing on 11 problem situations 2. 'Enhanced control' added discussion of same problems 3. 'Control' using Pomerleau and Pomerleau alone
Outcomes	Abstinence at 12 months (point prevalence) Validation: CO
Notes	1 and 2 treated as relapse prevention Condition 2 not displayed. 3/14 quit
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation method not described
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding not possible because of nature of the intervention, but all participants received same amount of contact, and no therapists had previous experience with stop‐smoking groups, hence performance bias unlikely
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemical validation used
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	5 pretreatment and 6 dropouts during treatment excluded, assignment not specified