Sims 2013.

Methods	Setting: Wisconsin, USA Recruitment: Young adult callers to the Wisconsin Tobacco Quit Line (WTQL)
Participants	410 smokers age 18 ‐ 24 years, smoked at least 1 cig in past 30 days and motivated to quit. 42% M; av. age 21.3 years, av. cigs/day 15
Interventions	1. S‐H only, stage‐based booklets 2. S‐H + up to 4 proactive cessation counselling calls over 4 ‐ 6 weeks through the WTQL
Outcomes	Abstinence at 6 m (7‐day PP) Self‐report
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	List of random numbers
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding of outcome assessment (detection bias) All outcomes	High risk	Abstinence not biochemically validated. Level of personal contact differed between arms
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	53% not followed in Intervention, 50% in Control. Missing treated as smoking. Responder analysis did not change results