Bock 2013.

Methods	Study design: RCT Country: USA Recruitment: advertisements in local media outlets, Internet sites, radio programmes, asking interested individuals to call or text Study date: 2011
Participants	Baseline characteristics(n = 60) Mean age: 30.7 (9.0) Female: 57% (N = 34) High school or less: 30% (N = 18) FTND: not stated White: 66% (N = 40) Inclusion criteria: current daily smoker, interested in quitting smoking in the next 30 days, have a mobile phone with SMS text messaging capability, use SMS messaging at least once monthly Exclusion criteria: not explicitly stated
Interventions	All participants received a single, individual 30‐min SC counselling session. TXT‐2‐Quit: an 8‐week programme with 1‐4 text messages/day (depending on quit stage). SC messages were tailored to the participant's stage of SC, with specialised messages provided on demand, based on user requests for additional support, and an optional peer‐to‐peer social support network Control: an 8‐week programme of daily non‐smoking‐related text messages
Outcomes	Primary outcome: self‐reported 7‐day point‐prevalence abstinence at 6 months
Funding source	National Institute on Drug Abuse
Conflicts of interest	None declared
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Simple randomisation via computerised random number generator
Allocation concealment (selection bias)	Low risk	Assignments in a sealed envelope delivered after completion of the baseline data collection
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Questionnaires were filled in online with minimal investigator contact
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only 2 participants in control group appeared to be missing at 6 months; ITT analysis presented