Optimizing the Carrot Rewards app: An examination of team-based financial incentives to increase walking

Mobile health applications (mHealth apps) targeting physical activity (PA) have increased in popularity, yet effectiveness is often limited by low engagement. This study examined the impact of adding a team-based feature, Step Together Challenges (STCs), to an existing incentive-based mHealth app (i.e., Carrot Rewards) on PA. A 24-week retrospective matched pairs study was conducted (n=61,170; pre-intervention: weeks 1-12; intervention: weeks 13-24). Participants who used STCs (experimental group) were matched with those who did not (controls). STC users could earn team incentives for collaboratively reaching individual daily step goals 10 times in seven days. Controlling for pre-intervention mean daily step count, ANCOVA showed a significant difference in intervention average steps per day ( ηp2=0.024). Linear regression show a dose-response relationship between number of STCs completed and intervention mean daily step count (adjusted R2=0.699). Introducing team-based incentives appears to increase PA in an mHealth context