Lennox 2001.

Methods	Setting: general practice, Scotland, UK Recruitment: smokers in general practices who returned questionnaires
Participants	2610 smokers; no demographic details
Interventions	No face‐to‐face contact ∙ Tailored letter from physician (4 pages) ‐ based on SoC; decisional balance and other indicators from questionnaire ∙ Untailored letter from physician (same format) ‐ included specific behavioural advice on quitting ∙ Control ‐ letter acknowledging questionnaire
Outcomes	Abstinence at 12 months (24 months' data reported but point prevalence, so does not represent a more conservative measure) Validation: saliva cotinine
Notes	2 vs 3, self‐help, no contact 1 vs 2, tailoring
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random numbers
Allocation concealment (selection bias)	Low risk	"After the questionnaires were returned, we randomised the participants to the groups" No participant contact; low risk of selection bias
Blinding (performance bias and detection bias) All outcomes	Low risk	Similar intervention intensities; no face‐to‐face contact; biochemical validation used
Incomplete outcome data (attrition bias) All outcomes	Low risk	22% loss to follow‐up; similar across groups; non‐responders counted as smokers