Willemsen 2006.

Methods	Setting: community, Netherlands Recruitment: smokers identified from a market research database; willing to participate in evaluation of an ‘information aid’
Participants	1014 smokers 'intending to quit'; 46% female, modal age 35 to 44 years, modal cpd 18 to 22, 86% daily smokers
Interventions	∙ Mailed Decision Aid: Starter’s Kit, including information about all major available treatment methods, classified into known effective and unknown; samples of materials and information on how to obtain them; video with descriptions of quitting experiences ∙ No intervention
Outcomes	Sustained abstinence at 6 months (quit for longer than ˜ 4 months) Validation: none
Notes	Self‐help vs control; aid had no effect on prolonged abstinence outcome used in meta‐analysis but did have an effect on point prevalence abstinence Aim of intervention was to increase use of efficacious aids, but it had no effect Study authors note that aid "did not contain any concrete self‐help information that the smokers might have put into practice"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised; method not stated
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding (performance bias and detection bias) All outcomes	High risk	Participants in control group aware that it was a trial of self‐help materials; never received materials, which could have artificially lowered control group quit rate
Incomplete outcome data (attrition bias) All outcomes	Low risk	11.8% lost at 6 months; intervention participants more likely to be missing at 2 weeks' but not at 6 months' follow‐up Losses included as smokers

4As: Ask, Advise, Assist, Arrange.
 ALA FfS: American Lung Association Freedom from Smoking programme.
 CCS: Canadian Cancer Society.
 CI: confidence interval.
 CO: carbon monoxide.
 cpd: cigarettes per day.
 FEV₁: forced expiratory volume in one second.
 FTND: Fagerstrom Test for Nicotine Dependence.
 GP: general practitioner.
 HEA: Health Education Authority.
 HMO: health maintenance organisation.
 ITT: intention to treat.
 MA: meta‐analysis.
 NCI: National Cancer Institute.
 NG: nicotine gum.
 NRT: nicotine replacement therapy.
 OR: odds ratio.
 ppm: parts per million.
 RR: risk ratio.
 SES: socioeconomic status.
 SoC: stage of change.
 TTM: transtheoretical model.
 TTQ: time to quit.
 VA: Veterans Administration.