Digital contact tracing apps have been introduced globally as an instrument to contain the COVID-19 pandemic. Yet, privacy by design impedes both the evaluation of these tools and the deployment of evidence-based interventions to stimulate uptake. We combine an online panel survey with mobile tracking data to measure the actual usage of Germany’s official contact tracing app and reveal higher uptake rates among respondents with an increased risk of severe illness, but lower rates among those with a heightened risk of exposure to COVID-19. Using a randomized intervention, we show that informative and motivational video messages have very limited effect on uptake. However, findings from a second intervention suggest that even small monetary incentives can strongly increase uptake and help make digital contact tracing a more effective tool.

数字接触者追踪应用程序已在全球范围内推出，作为遏制 COVID-19 大流行的工具。然而，设计的隐私既阻碍了对这些工具的评估，也阻碍了基于证据的干预措施的部署以刺激吸收。我们将在线小组调查与移动跟踪数据相结合，以衡量德国官方接触者追踪应用程序的实际使用情况，并揭示在重病风险增加的受访者中采用率较高，但在 COVID-19 风险较高的受访者中采用率较低- 19. 使用随机干预，我们表明信息和激励视频信息对吸收的影响非常有限。然而，第二次干预的结果表明，即使是很小的货币激励措施也可以极大地增加采用率，并有助于使数字接触者追踪成为更有效的工具。