de Vries 2008.

Methods	Setting: community, Netherlands Recruitment: telephone recruitment for a multiple risk factor health promotion intervention
Participants	156 smokers amongst 2827 participants, of whom 1331 (47%) responded at T4 Baseline all participants: 55% female, average age 49
Interventions	∙ Printed tailored letters on smoking as an identified risk factor (other targets were physical activity, nutrition); half of the group had action planning component in third letter ∙ Printed generic letters
Outcomes	Abstinence at 9 months (not defined) Validation: none
Notes	Effect of tailoring Numbers of smokers at baseline and numbers of quitters provided by study author
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised; method not described
Allocation concealment (selection bias)	Unclear risk	Details not given
Blinding (performance bias and detection bias) All outcomes	Low risk	No biochemical validation but interventions of similar intensity; differential misreport judged to be unlikely
Incomplete outcome data (attrition bias) All outcomes	High risk	Only baseline smokers who responded to follow‐up survey included in analysis