Intervention
All of the participants were informed that the eighth day after randomization would be their quit day. Participants who were randomized to the intervention group received the program of interventions (1-2 personalized text messages per day for 3 months).Control group participants received a smoking cessation intervention that used nonpersonalized text messages and was developed by the NCI. The NCI intervention was based on well-established cognitive-behavioral cessation approaches and contained 91 messages. Participants received approximately 1 message per day for 3 months. The text messages provided encouragement, practical advice to help maintain cessation, and information on the health effects of smoking. The details of the control intervention can be found elsewhere.