Recruitment
DISEASE, RECRUITMENT
We marketed the trial to smokers through print advertising (leaflets), digital advertising (the app), and staff from Shougang Technical College (teachers and leaders). Potential participants contacted the local Disease Control and Prevention Center to register their interest. The research assistants explained the study to each potential participant and preliminarily assessed his or her eligibility. All eligible smokers were told they needed to come to a location (typically the meeting room of the Disease Control and Prevention Center or a hotel) on a fixed date to finalize the recruitment process. Participant eligibility was confirmed, and all participants signed an informed consent form during the first face-to-face contact.