Augustson 2017.

Methods	Study design: RCT Country: China Recruitment: recruited from subscribers to Nokia Life Tools on Nokia phones in both urban and rural areas of China’s Zhejiang, Heilongjiang, and Shaanxi provinces Date of study: 2013
Participants	Baseline characteristics (n = 8000) Female %: not stated Mean age: not stated High school or lower education: not stated FTND: not stated White: not stated Inclusion criteria: Nokia Life Tools users; adult smokers Exclusion criteria: none specifically stated
Interventions	High‐frequency text contact (HFTC): 91 messages during the 6 weeks; 3 messages/day for weeks 1 and 2, 2/day for weeks 3‐5, and 1/day for week 6. At the end of each text message, participants in both groups were offered the opportunity to cancel the service via text. The text messages provided encouragement, practical advice to help maintain cessation, and information on the health effects of smoking. Low‐frequency text contact (LFTC): 1 text message/week, for a total of 6 text messages during the 6‐week intervention period; a subset of text messages on smoking’s health effects
Outcomes	Definition of abstinence: 7‐day point prevalence abstinence self‐reported via text message at 6‐month follow‐up
Funding source	National Cancer Institute, National Institutes of Health, U.S. Dept of Health Human Services
Conflicts of interest	None declared
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Intervention participants who opted into the phase 3 SC trial were randomly assigned to the intervention or comparison group (n ¼ 4000 in each group)" Therefore, participants were randomly assigned but it was not stated how
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome assessed by text message with no face‐to‐face contact Quote: "participants were not aware of the separate intervention arms and therefore did not know what group they were assigned to"
Incomplete outcome data (attrition bias) All outcomes	High risk	Loss to follow‐up clearly stated but > 50%; 58.4% of intervention group and 56.1% of control group lost to follow‐up at 6‐month assessment. ITT analysis