Gilbert 2013.

Methods	Setting: general practices, UK Recruitment: identified via GP records; mailed proactively
Participants	6697 current smokers aged 18 to 65 years, 56% female, average age 45, average cpd 18 (excluding 5.4% non‐daily smokers) 47% not planning to quit within 6 months
Interventions	∙ Standard, non‐tailored NHS: Stop Smoking Start Living booklet and computer tailored advice; report based on information obtained through baseline assessment questionnaire, letter from GP; follow‐up assessment via mail at 1 month; additional tailored mailing ∙ Standard, non‐tailored NHS: Stop Smoking Start Living booklet
Outcomes	3 months' sustained abstinence at 6 months Validation: none
Notes	214 participants excluded post randomisation for valid reasons
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Blocked randomisation codes were generated externally and given to an independent administrator in sealed envelopes upon receipt of completed questionnaires"
Allocation concealment (selection bias)	Low risk	"Participants were accepted into the study before knowledge of the next assignment in the sequence in order to minimise selection bias. Each study participant randomised received the treatment corresponding to the next free study number in the randomised sequence"
Blinding (performance bias and detection bias) All outcomes	High risk	No biochemical validation; participants aware of what other condition was receiving "Participants were told that they would be sent some information about quitting, and could be randomly selected to receive additional information based on their answers in the questionnaire"
Incomplete outcome data (attrition bias) All outcomes	Low risk	27% lost intervention, 24% lost control; no significant differences in predictors of dropouts between groups Study authors conducted sensitivity analyses with alternative assumptions about dropouts