Examining Responsiveness to an Incentive-Based Mobile Health App: Longitudinal Observational Study

Area of Science:

• Digital Health
• Behavioral Economics
• Health Informatics

Background:

• The Carrot Rewards app aimed to increase health knowledge and behaviors by rewarding users with loyalty points for engagement.
• Program design elements were adjusted early in the rollout, leading to variations in user engagement.
• Understanding these variations is key to optimizing mHealth app effectiveness.

Purpose of the Study:

• To analyze the impact of reward size reduction over time on user engagement.
• To investigate how other features like quiz timing, intervention content, and reward type influence engagement with a mobile health app.

Main Methods:

• A longitudinal, nonexperimental observational study of British Columbia citizens who downloaded the Carrot Rewards app.
• Regression methodology was employed to assess the influence of program design changes on user engagement and offer acceptance.

Main Results:

• User engagement was most strongly influenced by reward type (e.g., movies, air travel, groceries), followed by time delay for offers, health intervention content, and lastly, changes in points offered.
• A 10% reduction in points led to only a 1% decrease in offer response likelihood.
• Reward type, timing, and content had a greater impact on user retention than point value adjustments.

Conclusions:

• The mHealth app successfully drove high engagement by applying behavioral economics principles, offering instant rewards.
• Reward point value is less critical for sustained engagement than the type of reward, offer timing, and intervention content.
• These findings offer insights for designing effective mobile health interventions.