Privacy, Adoption, and Truthful Reporting: A Simple Theory of Contact Tracing Applications

This short paper analyses the trade-offs associated with the deployment of contact tracing applications to support policy responses in the pandemic. In many jurisdictions, the government cannot force individuals to adopt such applications. We therefore analyze a simple model that highlights the importance of individuals' incentives to voluntarily adopt a reporting application and reveal their infection status to the government who can then undertake contact monitoring. We discuss the consequences of various policy options, such as security, communication and anonymisation policies, in terms of the size and representativeness of the sample of infection data that contract tracing applications generate.