Chan 2015.

Methods	Study design: RCT Country: China Recruitment: recruitment activities for the Quit to Win Contest took place at shopping malls or public areas in 16 out of the 18 districts in Hong Kong during May‐July 2009. Participants who expressed an interest in joining the contest were screened for eligibility and tested on their exhaled CO to ascertain their smoking status Study year: 2009
Participants	Baseline characteristics (n = 1003) Female: 8.2% Education level primary or below: 21.6% White: not stated Age group: 49.1% aged 40‐59 years Nicotine dependency (Heaviness of Smoking Index): 32.6% Heavy Inclusion criteria: eligible participants were (1) Hong Kong residents aged ≥ 18 years; (2) daily smokers who smoked at least 1 cigarette/day in the past 6 months; (3) exhaled CO of ≥ 4 ppm; (4) able to communicate in Cantonese and read Chinese and (5) had a mobile phone to receive SMS. Exclusion criteria: smokers who were physically or mentally unable to communicate or currently following other forms of SC programme were excluded from this RCT.
Interventions	All participants were given an 8‐page self‐help SC booklet. TEL Group: 5‐min telephone SC counselling by a trained nurse within 7 days of enrolment SMS Group: 8 mobile telephone text messages that were constructed with reference to the 8‐page SC booklet Control Group: self‐help booklet and the contact information of the SC services at the enrolment
Outcomes	Definition of abstinence: biochemically validated 7‐day point prevalence at 12‐month follow‐up
Funding source	Hong Kong Council on Smoking and Health (chairman and executive director are co‐authors)
Conflicts of interest	TH Lam is the principal investigator of the FAMILY project, which was funded by the Hong Kong Jockey Club Charities Trust.
Notes	The control and SMS group were used in the comparison of text messaging with minimal SC support, and the SMS group and TEL group were used in the comparison of text messaging with other SC support
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "To achieve balanced number of subjects in each arm, the allocation sequence was sequentially generated by the author based on block randomization (with each recruitment session as a block) using the web site http://www.random.org."
Allocation concealment (selection bias)	Unclear risk	Quote: "The randomization and allocation were conducted by the author who did not participate in subject recruitment to ensure allocation concealment."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Follow‐up calls were made to all the participants at 2, 6 and 12 months after the enrolment with standardized questionnaires by trained interviewers who were blinded to the group assignment." Quote: "The RCT was single‐blinded that all recruitment staff and assessors were not aware of the group allocation at the follow‐up assessment." Biochemical validation of abstinence was used.
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT analysis, at 6 months 66.9%, 73.1% and 70.6% of the 3 groups were available at follow‐up