Electronic Thesis and Dissertation Repository

Thesis Format



Master of Arts




Mitchell, Marc S.

2nd Supervisor

Prapavessis, Harry.



BACKGROUND: Government interest in using financial incentives (FIs) to stimulate physical activity (PA) is increasing. The cost of longer-term incentive interventions may be prohibitive, however. PURPOSE: To examine the impact of FI withdrawal on PA. METHODS: A 25-week retrospective pre-post quasi-experimental study was conducted with users of a FI-based mHealth app. Users from three Canadian provinces were included. Daily FI were removed in Ontario (ON; intervention) but not British Columbia (BC) and Newfoundland and Labrador (NL; control). Simple linear regression models were used to examine weekly mean daily step count after FI withdrawal. RESULTS: The total sample included 584,760 users (Female: 63.5%; Age: 34.3 years). Following FI withdrawal, weekly mean daily step count decreased in all provinces with the largest decrease observed in ON (i.e., 198 and 274 fewer steps/day vs. BC and NL, respectively). CONCLUSION: These findings may be relevant for governments looking to deploy time-limited FI-based PA programs.

Summary for Lay Audience

To address the global physical inactivity pandemic, there is an urgent need for governments and corporations to implement sustainable and scalable population-level physical activity interventions. Incentive-based interventions delivered through smartphone apps can increase physical activity at the population-level and be cost-effective. However, effective strategies to remove financial incentives that maintain increases in physical activity are urgently needed for governments and corporations who cannot afford to continuously finance incentive-based interventions. This was a 25-week study that examined the impact of removing financial incentives for physical activity among 584,760 users of Carrot Rewards, a popular Canadian mobile health application. Users were categorized into subgroups to explore whether specific user characteristics influenced the impact of financial incentive removal on physical activity. Financial incentives for physical activity were removed in Ontario on Study Week 13 but were provided for 25-weeks in British Columbia and Newfoundland and Labrador. Declines in physical activity were greatest in Ontario relative to British Columbia and Newfoundland and Labrador. Furthermore, Ontario users who interacted with Carrot Rewards at the highest frequency and were the most physically active experienced the greatest decrease in physical activity after financial incentive removal. Length of exposure to Carrot Rewards, age and gender did not appear to influence the effect of financial incentive removal on physical activity. Given our study’s sample size and real-world design, these findings may be applicable to governments and corporations with ongoing or planned incentive-based physical activity interventions delivered through smartphone applications at a population-level.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.