Lando 1991.

Methods	Setting: community cardiovascular risk factor screening programme, USA Recruitment: smokers identified from screening programme who agreed to take part
Participants	570 smokers, approx 50% female, average age 42, average cpd 20
Interventions	No face‐to‐face contact ∙ Self‐help Quit for Good materials (NCI) ∙ Self‐help Quit and Win materials ‐ a more extensive and structured programme ∙ Wait‐list control
Outcomes	Abstinence 7 months after randomisation (but only 3 to 4 months after receipt of materials) Validation: none
Notes	Items in first and second bullets above treated as self‐help programmes; no difference in results between them Both intervention and control participants likely to have been exposed to simultaneous community Quit and Win contests Study author notes that a number of participants quit between randomisation and receipt of materials
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised; method not described
Allocation concealment (selection bias)	Unclear risk	No details given; significant differences between intervention and control for sex and education; higher confidence in quitting among controls
Blinding (performance bias and detection bias) All outcomes	High risk	Wait‐list control
Incomplete outcome data (attrition bias) All outcomes	Low risk	25 lost to follow‐up, of whom 13 were in control groups Denominators are those followed up