Participants enrolled online using Way to Health, an automated technology platform based at the University of Pennsylvania that integrates wireless devices, conducts clinical trial randomization and enrollment processes, delivers messaging (text message or e-mail) and surveys, automates transfers of financial incentives, and securely captures data for research purposes (31 ). Way to Health was used in prior behavioral intervention studies (32 (link)–34 (link)). All participants received $25 for enrolling and $75 for participating through the primary end point at 13 weeks along with completion of a survey on their experience. However, there was no participation incentive for the follow-up period. Participants were mailed a bank check at the end of each month with all accumulated earnings. All participants selected whether they preferred to receive study communications by e-mail, text message, or both.
Participants were electronically randomly assigned to the control group or to 1 of 3 intervention groups with an equivalent expected economic value of $1.40, which is a value used in prior work (34 (link)). For 26 weeks, participants in all 4 groups received daily feedback on whether they had achieved the 7000-step goal in the prior day. The control group received no other intervention aside from daily feedback. For the 13-week intervention, the intervention groups included a gain incentive in which participants received $1.40 for each day they met the goal, a loss incentive in which $1.40 was taken away from a monthly incentive ($42 allocated upfront) each time the daily goal was not met, or a daily lottery incentive. Persons in the lottery-incentive group selected a 2-digit number between 00 and 99. One winning number was randomly selected daily during the intervention period. If a participant’s number had a single-digit match (an 18% chance), he or she won $5. If the participant’s number had a 2-digit match (a 1% chance), he or she won $50. Participants were eligible to collect the reward only if the 7000-step goal was achieved on the prior day. Ineligible participants were informed what they would have won if they had achieved the goal, drawing on evidence that the desire to avoid regret can be motivating (23 , 24 , 35 (link), 36 ). Incentives were offered only during the 13-week intervention, but daily performance feedback was delivered for the entire 26 weeks.
Participants were electronically randomly assigned to the control group or to 1 of 3 intervention groups with an equivalent expected economic value of $1.40, which is a value used in prior work (34 (link)). For 26 weeks, participants in all 4 groups received daily feedback on whether they had achieved the 7000-step goal in the prior day. The control group received no other intervention aside from daily feedback. For the 13-week intervention, the intervention groups included a gain incentive in which participants received $1.40 for each day they met the goal, a loss incentive in which $1.40 was taken away from a monthly incentive ($42 allocated upfront) each time the daily goal was not met, or a daily lottery incentive. Persons in the lottery-incentive group selected a 2-digit number between 00 and 99. One winning number was randomly selected daily during the intervention period. If a participant’s number had a single-digit match (an 18% chance), he or she won $5. If the participant’s number had a 2-digit match (a 1% chance), he or she won $50. Participants were eligible to collect the reward only if the 7000-step goal was achieved on the prior day. Ineligible participants were informed what they would have won if they had achieved the goal, drawing on evidence that the desire to avoid regret can be motivating (23 , 24 , 35 (link), 36 ). Incentives were offered only during the 13-week intervention, but daily performance feedback was delivered for the entire 26 weeks.
