Smartphone-based contact-tracing apps are a promising solution to help scale up the conventional contact-tracing process. However, low adoption rates have become a major issue that prevents these apps from achieving their full potential. In this paper, we present a national-scale survey experiment ($N=1963$) in the U.S. to investigate the effects of app design choices and individual differences on COVID-19 contact-tracing app adoption intentions. We found that individual differences such as prosocialness, COVID-19 risk perceptions, general privacy concerns, technology readiness, and demographic factors played a more important role than app design choices such as decentralized design vs. centralized design, location use, app providers, and the presentation of security risks. Certain app designs could exacerbate the different preferences in different sub-populations which may lead to an inequality of acceptance to certain app design choices (e.g., developed by state health authorities vs. a large tech company) among different groups of people (e.g., people living in rural areas vs. people living in urban areas). Our mediation analysis showed that one’s perception of the public health benefits offered by the app and the adoption willingness of other people had a larger effect in explaining the observed effects of app design choices and individual differences than one’s perception of the app’s security and privacy risks. With these findings, we discuss practical implications on the design, marketing, and deployment of COVID-19 contact-tracing apps in the U.S.

基于智能手机的接触者追踪应用程序是一种很有前途的解决方案，可以帮助扩大传统的接触者追踪过程。然而，低采用率已成为阻碍这些应用程序充分发挥其潜力的主要问题。在本文中，我们提出了一个全国范围的调查实验（$否=\mathrm{1963年}$) 在美国调查应用程序设计选择和个体差异对 COVID-19 接触者追踪应用程序采用意向的影响。我们发现，亲社会性、COVID-19 风险认知、一般隐私问题、技术准备情况和人口统计因素等个体差异比应用程序设计选择（例如去中心化设计与集中式设计、位置使用、应用程序提供商和安全风险的呈现。某些应用程序设计可能会加剧不同子人群的不同偏好，这可能导致不同人群（例如，人们生活在农村地区与生活在城市地区的人）。我们的中介分析表明，一个人对应用程序提供的公共健康益处的看法和其他人的采用意愿在解释应用程序设计选择和个体差异的观察效果方面比一个人对应用程序的安全和隐私风险的看法有更大的影响。根据这些发现，我们讨论了在美国设计、营销和部署 COVID-19 接触者追踪应用程序的实际意义