Aveyard 2003.

Methods	Setting: 65 general practices, UK Recruitment: volunteers from random selection of smoking patients; not selected for motivation
Participants	2471 smokers, 1373 in relevant arms, > 80% in pre‐contemplation or contemplation, 10% to 14% in preparation 54% female, average age 41, average cpd 20
Interventions	No face‐to‐face contact ∙ Standard self‐help materials, single mailing ∙ Self‐help manual based on transtheoretical (SoC) model; expert system letter tailored on baseline questionnaire. Further questionnaires at 3 months and 6 months for additional letters (approximately 50% received 3 letters)
Outcomes	Abstinence at 12 months, sustained for 6 months Validation: saliva cotinine < 14.2 ng/mL
Notes	2 vs 1; tailored self‐help vs standard self‐help
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation using minimisation to balance SoC, addiction, and socioeconomic status
Allocation concealment (selection bias)	Low risk	Baseline questionnaires read optically and data transferred automatically to the Access database, which performed the minimisation
Blinding (performance bias and detection bias) All outcomes	Low risk	Interventions of similar intensity 12 months: abstinence "was confirmed with salivary cotinine, so that we had unconfirmed and confirmed prevalence of quitting" Confirmed figures used in analysis
Incomplete outcome data (attrition bias) All outcomes	Low risk	24% of self‐help and 24% of control lost to follow‐up Included in ITT analysis here; sensitivity analyses allowing for differential dropout did not change findings