Prochaska 1993.

Methods	Setting: community, USA Recruitment: advertisements for volunteers to test self‐help materials
Participants	756 smokers (93 pre‐contemplation, 435 contemplation, 228 preparation; 569 in relevant arms); average age 43, average cpd 27
Interventions	∙ Standard self‐help ‐ ALA FfS, A Lifetime of Freedom from Smoking, 50 Most Often Asked Questions ∙ Targeted manuals ‐ 5 covering pre‐contemplation, contemplation, action, maintenance, and relapse. Participants were sent manual for their SoC and subsequent ones, except for relapse, which was sent following an assessment at which relapse occurred ∙ Tailored Interactive ‐ in addition to manuals, participants were sent personalised reports in response to questionnaires ∙ Counsellor telephone calls ‐ same as third bullet above with short calls at 0, 1, 3, and 6 months (not included in this review)
Outcomes	Sustained abstinence at 18 months (12 months and 18 months) Validation: none; participants were asked for names of significant others but these were not contacted
Notes	2 vs 1 targeting, 3 vs 2 tailoring Numbers randomised and quit rates as shown on graphs obtained from study authors
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised; method not stated; stratified by SoC
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding (performance bias and detection bias) All outcomes	Low risk	"Bogus pipeline" approach; names of significant others asked for but not contacted Similar intensities across interventions (all received manuals)
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition at each assessment averaged 5.5% ‐ not significantly different across conditions Non‐respondents included as smokers in meta‐analysis