Hall 1985.

Methods	Setting: clinic, USA Recruitment: referred by physicians, friends or self
Participants	84 smokers in relevant arms; 53% M, av age 38, av cpd 30.5 Therapists: 2 psychologists
Interventions	Pharmacotherapy: NRT; gum (2 mg, available for 6 months) 1. Intensive behavioural treatment (incl relapse prevention skill training, relaxation, 30 seconds aversive smoking of 3 cigs). 14 x 75 min sessions over 8 weeks 2. Low‐contact . Met x 4 in 3 weeks, educational materials, written exercises, group discussion 3. Intensive behavioural, no gum. Not included in this review
Outcomes	Abstinence at 52 weeks (assume PP) Validation: CO < 10 ppm, thiocyanate < 85 mg/mL, reports of significant others (biochemical measures failed to confirm self‐report in 3 instances)
Source of Funding/CoI	National Institute on Drug Abuse. No declarations of interest
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomly assigned within time constraints." Author clarification: "There were two or more treatment conditions available within any time block, and participants were randomly assigned to conditions within that time block".
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemically validated
Incomplete outcome data (attrition bias) All outcomes	Low risk	3 dropouts from group 2 and 3 from group 3. Assumed to be included in denominator for reported % abstinent used to derive numbers quit