McCarthy Hannah, Potts Henry W W, Fisher Abigail
University College London, London, United Kingdom.
JMIR Form Res. 2024 Dec 10;8:e50041. doi: 10.2196/50041.
Financial incentives delivered via apps appear to be effective in encouraging physical activity. However, the literature on different incentive strategies is limited, and the question remains whether financial incentives offer a cost-effective intervention that could be funded at the population level.
This study aimed to explore patterns of tracked physical activity by users of an incentive-based app before and after a change in incentive strategy. A business decision to alter the incentives in a commercially available app offered a natural experiment to explore GPS-tracked data in a retrospective, quasi-experimental study. The purpose of this exploratory analysis was to inform the design of future controlled trials of incentives delivered via an app to optimize their usability and cost-effectiveness.
Weekly minutes of tracked physical activity were explored among a sample of 1666 participants. A Friedman test was used to determine differences in physical activity before and after the change in incentive strategies. Post hoc Wilcoxon tests were used to assess minutes of physical activity in the 2 weeks before and after the change. A secondary analysis explored longitudinal patterns of physical activity by plotting the mean and median minutes of physical activity from 17 weeks before and 13 weeks after the change in incentive strategy. CIs were calculated using bias-corrected bootstraps. Demographics were also explored in this way.
There were significant differences in the weekly minutes of activity before and after the change in incentive strategy (Friedman χ=42, P<.001). However, a longitudinal view of the data showed a more complex and marked variation in activity over time that undermined the conclusions of the before/after analysis.
Short-term before-and-after observational studies of app-tracked physical activity may result in misleading conclusions about the effectiveness of incentive strategies. Longitudinal views of the data show that important fluctuations are occurring over time. Future studies of app-tracked physical activity should explore such variations by using longitudinal analyses and accounting for possible moderating variables to better understand what an effective incentive might be, for whom, and at what cost.
通过应用程序提供的经济激励措施似乎能有效鼓励体育活动。然而，关于不同激励策略的文献有限，经济激励措施是否能提供一种具有成本效益的干预措施，且这种措施能否在人群层面获得资金支持，这一问题仍然存在。
本研究旨在探讨激励策略改变前后，基于激励的应用程序用户所记录的体育活动模式。一项关于改变一款商业应用程序中激励措施的商业决策，提供了一个自然实验，用于在一项回顾性、准实验性研究中探索通过GPS记录的数据。这项探索性分析的目的是为未来通过应用程序提供激励措施的对照试验设计提供参考，以优化其可用性和成本效益。
在1666名参与者的样本中，对每周记录的体育活动分钟数进行了研究。使用Friedman检验来确定激励策略改变前后体育活动的差异。事后Wilcoxon检验用于评估激励策略改变前后两周的体育活动分钟数。二次分析通过绘制激励策略改变前17周和改变后13周体育活动的平均和中位数分钟数，探讨了体育活动的纵向模式。使用偏差校正自助法计算置信区间。人口统计学数据也以这种方式进行了探索。
激励策略改变前后，每周活动分钟数存在显著差异（Friedman χ=42，P<.001）。然而，数据的纵向视图显示，随着时间的推移，活动存在更复杂且明显的变化，这削弱了前后分析的结论。
对应用程序记录的体育活动进行的短期前后观察性研究，可能会得出关于激励策略有效性的误导性结论。数据的纵向视图表明，随着时间的推移会出现重要的波动。未来关于应用程序记录的体育活动的研究，应通过纵向分析并考虑可能的调节变量来探索此类变化，以更好地理解什么可能是有效的激励措施、对谁有效以及成本是多少。
