Investigating Rewards and Deposit Contract Financial Incentives for Physical Activity Behavior Change Using a Smartphone App: Randomized Controlled Trial

David R de Buisonjé   ¹ , MSc ;   Thomas Reijnders   ^{1, 2} , PhD ;   Talia R Cohen Rodrigues   ¹ , MSc ;   Santhanam Prabhakaran   ³ , MSc ;   Tobias Kowatsch   ^{3, 4, 5} , Prof Dr ;   Stefan A Lipman   ⁶ , PhD ;   Tammo H A Bijmolt   ⁷ , Prof Dr ;   Linda D Breeman   ¹ , PhD ;   Veronica R Janssen   ^{1, 8} , PhD ;   Roderik A Kraaijenhagen   ⁹ , MD, PhD ;   Hareld M C Kemps   ¹⁰ , MD, PhD ;   Andrea W M Evers   ^{1, 11} , Prof Dr

¹ Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, Leiden, Netherlands

² Department of Human-Centered Design, Faculty of Industrial Design Engineering, Delft University of Technology, Delft, Netherlands

³ Centre for Digital Health Interventions, Department of Management, Technology, and Economics, ETH Zurich, Zurich, Switzerland

⁴ Institute for Implementation Science in Health Care, University of Zurich, Zurich, Switzerland

⁵ School of Medicine, University of St. Gallen, St. Gallen, Switzerland

⁶ Erasmus School of Health Policy & Management, Erasmus University Rotterdam, Rotterdam, Netherlands

⁷ Faculty of Economics and Business, University of Groningen, Groningen, Netherlands

⁸ Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands

⁹ Hearts4People Foundation, Amsterdam, Netherlands

¹⁰ Department of Cardiology, Máxima Medical Center, Veldhoven, Netherlands

¹¹ Medical Delta, Leiden University, Technical University Delft, Erasmus University, Delft, Netherlands