Ledwith 1984.
Methods | Setting: community, Scotland, UK Recruitment: newspaper advertisements for a smoker's advice centre | |
Participants | 1839 smokers responding to offers of advice on stopping smoking | |
Interventions | No face‐to‐face contact ∙ No advice control ∙ Self‐help leaflet with standard letter ∙ Self‐help leaflet and offer of individual advice upon returning a questionnaire | |
Outcomes | Abstinence at 12 months (for 10 months or longer ‐ based on self‐report) Validation: attempt to obtain saliva for thiocyanate but not complete; data based on self‐report only | |
Notes | 2 vs 1, self‐help 3 vs 2, effect of tailored advice Only 34% returned baseline questionnaire to initiate tailored component No information about contents of leaflet Borderline whether this counts as a structured self‐help programme |
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Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Unclear risk | "Assigned at random"; method not described |
Allocation concealment (selection bias) | Unclear risk | No details given |
Blinding (performance bias and detection bias) All outcomes | Low risk | Although attempts to get biochemical validation were unsuccessful, control group was unaware of other treatment assignments; no face‐to‐face contact was given, hence differential misreport was judged to be unlikely |
Incomplete outcome data (attrition bias) All outcomes | Unclear risk | 16% lost to follow‐up Non‐respondents included as smokers |