Janz 1987.

Methods	Setting: 2 outpatient medical clinics, USA Recruitment: all smokers attending and giving informed consent for a study of health practices (unselected)
Participants	250 smokers, average age 46, average cpd 24
Interventions	∙ Control ‐ no intervention; clinic physicians not aware of the study (not included in the review) ∙ Advice from the physician and brief consultation with a nurse ∙ As second bullet above and the Step‐by‐Step Quit Kit
Outcomes	Abstinence at 6 months (ascertainment by telephone by independent interviewer) Validation: none
Notes	3 vs 2 for effect of self‐help as adjunct to advice Graphed percentages based on numbers followed up It has not been possible to obtain data from the study authors
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Pseudo‐random assignment of half‐day clinic sessions to experiment or control (control does not contribute to this review) Within experiment clinics, participants randomised to manual or no manual condition; method not described
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding (performance bias and detection bias) All outcomes	Low risk	No biochemical validation but interventions tested in this review included same amount of face‐to‐face contact and self‐report collection procedures designed to minimise misreport (research personnel made clear they had no relationship to healthcare team and responses were confidential)
Incomplete outcome data (attrition bias) All outcomes	Low risk	39 (16%) lost to follow‐up at 6 months "Drop‐out rates did not vary significantly across study groups" Losses not given by group, so not included in meta‐analysis