There is overwhelming evidence that adding financial incentives to existing interventions for health behaviour change improves their efficacy. However, there are still questions regarding the sustainability of the effects after the incentives have been removed and what would be the optimal design of an incentive. Furthermore, a major challenge for large-scale implementation of financial incentives is that the incentives need to be provided by third parties, requiring large amounts of funding. A solution to these issues could be to make use of deposit contracts, a special form of financial incentives in which participants deposit their own money, providing their own incentives to achieve a health goal. Roger et al. (2014) describe a deposit contract in more detail as a: “form of commitment device that enforces people’s voluntarily imposed restrictions until they have accomplished their goals”. Besides allowing for large scale implementation without the need for external funding, deposit contracts show additional advantages over a regular financial incentive, such as exploiting the mechanism of loss aversion. However, one possible obstacle for the uptake of deposit contracts is the necessary personal contribution that participants would have to make and risk losing. This might limit the actual uptake of deposit contracts. Very little research has been done on investigating the effects of deposit contracts for increasing physical activity (Mitchell et al., 2019). Three randomized controlled trials have used framing to create a deposit-like incentive (Patel et al., 2016) and one feasibility study has employed an actual deposit contract but with a small sample size (n=19)(Washington et al., 2016). The before mentioned three randomized controlled trials operationalized a deposit contract by framing a regular reward incentive as a loss. This loss frame was created by first telling participants that they would receive money at the start of the intervention and then, over the course of the experiment, having them lose some of ‘their’ money if they do not meet their walking goals (Patel et al., 2016). The results of these studies are inconsistent. Firstly, Burns et al (2018) showed that loss framed incentives and regular reward incentives had comparable effects on physical activity. In contrast, Patel et al. (2016) showed that a loss framed incentive had superior effects on physical activity compared to a gain framed incentive and a lottery incentive. Finally, Budworth et al. (2019) suggest that the combination of loss frame and a regular reward incentive was more acceptable and effective than either condition alone. The only study that employed actual deposits of participants own money was performed with 19 participants and showed promising preliminary results with deposit conditions being equally effective as no deposit conditions (Washington et al., 2016). No head-to-head comparisons of framing effects and deposit effects have been done yet. While an operationalization of deposit contracts with loss framing avoids issues with low uptake and utilizes loss aversion, it does not require participants to make an actually deposit of their own money. Requiring an actual deposit of participants’ own money could lead to stronger behavioral effects through increased feelings of loss and increased goal commitment. Furthermore, even when deposit incentives would not show superior but equal effects compared to reward incentives, this form of self-provided financial incentive would have crucial implementation advantages because no external funding is required.

The present study aims to explore (1) whether requiring an actual personal monetary deposit leads to higher effectiveness, (2) whether framing a financial incentive as a loss leads to higher effectiveness, and (3) whether there is a synergistic effect between these factors wherein the effect of requiring a personal deposit is increased further when it is framed as a loss.

The study is implemented with the help of the open source intervention platform, MobileCoach.

Mitchell, M. S., Orstad, S. L., Biswas, A., Oh, P. I., Jay, M., Pakosh, M. T., & Faulkner, G. (2019). Financial incentives for physical activity in adults: systematic review and meta-analysis. British journal of sports medicine, bjsports-2019.
Patel, M. S., Asch, D. A., & Volpp, K. G. (2016). Framing financial incentives to increase physical activity among overweight and obese adults. Annals of internal medicine, 165(8), 600-600.
Donlin Washington, W., McMullen, D., & Devoto, A. (2016). A matched deposit contract intervention to increase physical activity in underactive and sedentary adults. Translational Issues in Psychological Science, 2(2), 101.

Prabhakaran Santhanam, Sascha Gfeller, Prof. Dr. Elgar Fleisch & Prof. Dr. Tobias Kowatsch

David de Buisonjé &Talia Cohen Rodrigues, Phd Candidates, Universiteit Leiden

Prabhakaran Santhanam