Title
Less stick more carrot? Increasing the uptake of deposit contract financial incentives for physical activity: A randomized controlled trial
Author
de Buisonjé, David R. (Universiteit Leiden)
Reijnders, T. (TU Delft Design Aesthetics; Universiteit Leiden)
Cohen Rodrigues, Talia R. (Universiteit Leiden)
Santhanam, Prabhakaran (ETH Zürich)
Kowatsch, Tobias (ETH Zürich; University of Zürich; University of St. Gallen)
Breeman, Linda D. (Universiteit Leiden)
Janssen, Veronica R. (Universiteit Leiden; Leiden University Medical Center)
Kraaijenhagen, Roderik A. (Hearts4people Foundation)
Kemps, Hareld M.C. (Maxima Medical Center, Veldhoven; Eindhoven University of Technology)
Evers, A.W.M. (TU Delft Applied Ergonomics and Design; Universiteit Leiden; Erasmus Universiteit Rotterdam)
Date
2024
Abstract
Background: Financial incentives are a promising tool to help people increase their physical activity, but they are expensive to provide. Deposit contracts are a type of financial incentive in which participants pledge their own money. However, low uptake is a crucial obstacle to the large-scale implementation of deposit contracts. Therefore, we investigated whether (1) matching the deposit 1:1 (doubling what is deposited) and (2) allowing for customizable deposit amounts increased the uptake and short term effectiveness of a deposit contract for physical activity. Methods: In this randomized controlled trial, 137 healthy students (age M = 21.6 years) downloaded a smartphone app that provided them with a tailored step goal and then randomized them to one of four experimental conditions. The deposit contract required either a €10 fixed deposit or a customizable deposit with any amount between €1 and €20 upfront. Furthermore, the deposit was either not matched or 1:1 matched (doubled) with a reward provided by the experiment. During 20 intervention days, daily feedback on goal progress and incentive earnings was provided by the app. We investigated effects on the uptake (measured as agreeing to participate and paying the deposit) and effectiveness of behavioral adoption (measured as participant days goal achieved). Findings: Overall, the uptake of deposit contracts was 83.2%, and participants (n = 113) achieved 14.9 out of 20 daily step goals. A binary logistic regression showed that uptake odds were 4.08 times higher when a deposit was matched (p = .010) compared to when it was not matched. Furthermore, uptake odds were 3.53 times higher when a deposit was customizable (p = .022) compared to when it was fixed. Two-way ANCOVA showed that matching (p = .752) and customization (p = .143) did not impact intervention effectiveness. However, we did find a marginally significant interaction effect of deposit matching X deposit customization (p = .063, ηp2 = 0.032). Customization decreased effectiveness when deposits were not matched (p = .033, ηp2 = 0.089), but had no effect when deposits were matched (p = .776, ηp2 = 0.001). Conclusions: We provide the first experimental evidence that both matching and customization increase the uptake of a deposit contract for physical activity. We recommend considering both matching and customization to overcome lack of uptake, with a preference for customization since matching a deposit imposes significant additional costs. However, since we found indications that customizable deposits might reduce effectiveness (when the deposits are not matched), we urge for more research on the effectiveness of customizable deposit contracts. Finally, future research should investigate which participant characteristics are predictive of deposit contract uptake and effectiveness. Pre-registration: OSF Registries, https://osf.io/cgq48.
Subject
Behavior change
Deposit contracts
eHealth
Financial incentives
Physical activity
Rewards
To reference this document use:
http://resolver.tudelft.nl/uuid:6c851b17-4bde-48d5-84f4-b43220d9c3dc
DOI
https://doi.org/10.1016/j.psychsport.2023.102532
ISSN
1469-0292
Source
Psychology of Sport and Exercise, 70
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2024 David R. de Buisonjé, T. Reijnders, Talia R. Cohen Rodrigues, Prabhakaran Santhanam, Tobias Kowatsch, Linda D. Breeman, Veronica R. Janssen, Roderik A. Kraaijenhagen, Hareld M.C. Kemps, A.W.M. Evers