Research investigates potential benefits, limitations of using contact tracing apps

As long as contact tracing apps are carefully constructed and the information they reveal is appropriately safeguarded, such apps may, in conjunction with actual human tracing, have a role to play in the country’s public health response to the COVID-19 pandemic, says a team of experts from York University, the University of Toronto and Ontario Tech University.

In a research paper titled “Test, Trace, and Isolate: COVID-19 and the Canadian Constitution,” the seven authors consider the potential benefits and limitations of using contact tracing apps to identify people who have been exposed to COVID-19. They look at the privacy implications of different app design choices, and how those privacy impacts could be evaluated under the Canadian Charter of Rights and Freedoms, which provides a framework for balancing competing rights and interests.

Francois Tanguay Renaud
Francois Tanguay-Renaud

“We know that contact tracing is essential to controlling infectious disease and has a central role to play in determining when we can safely loosen COVID-19 physical distancing measures and reopen the economy,” said Professor François Tanguay-Renaud of York University’s Osgoode Hall Law School.

“Before the country goes further down the digital contact tracing road, we wanted to look at several issues surrounding the use of contact tracing apps including how to integrate such apps and human contact tracing; possible infringement of privacy rights; and the need to balance various Charter rights and values.”

Tanguay-Renaud wrote the paper with Lisa M. Austin, Vincent Chiao and Martha Shaffer, University of Toronto Faculty of Law; Beth Coleman, University of Toronto, ICCIT/Faculty of Information; David Lie, University of Toronto, Department of Electrical and Computer Engineering and Andrea Slane, Ontario Tech University, Faculty of Social Science and Humanities.

The authors had an extensive hour-long briefing (via Zoom) with federal Justice Minister David Lametti May 29.

“I must say that he was very receptive and liked many aspects of our paper. In particular, the need to take seriously into account the effectiveness of any app in tracing contacts with COVID cases, when assessing the necessity and proportionality of any infringement of Charter-protected interests, such as privacy, that such apps would likely involve,” Tanguay-Renaud said.

The study looks at the potential benefits and limitations of using contact tracing apps to identify people who have been exposed to COVID-19

The paper makes three major observations about the efficacy of contact tracing apps:

Improving the efficiency of human contact tracing
The public health goal of a contact tracing app should be to integrate with human contact tracing and make it more efficient rather than replace it, the paper notes. “We need to keep humans in the loop to ensure accuracy and to maintain the important social functions of contact tracing, which includes educating people about risks and helping them access social supports.”

Privacy choices
The paper points out that currently the most privacy-protective design for contact tracing apps makes use of proximity data (via Bluetooth) through a decentralized design, and that this method is receiving significant technical support from Apple and Google.

“However, this method fails to integrate with the human contact tracing system. Other options, such as the use of location logs or a centralized registration system, are more aligned with the public health goal of integration with human contact tracing but raise additional privacy questions.” What’s more, Google and Apple “prohibit app developers both from utilizing centralized methods and from utilizing location data.”

Constitutional balancing
Our privacy commissioners have discussed the need to assess these privacy choices according to the principles of necessity and proportionality, the paper notes. “The Canadian Charter requires that we choose the most privacy-protective app design that meets the public health goal, so long as the benefits of meeting this goal outweigh its deleterious effects on privacy. This requires a reasonable belief in the efficacy of such an app. It also requires an assessment of the nature of the benefits, which are not just the economic benefits of reopening the economy.”

Current restrictions on movement and work are themselves limitations of basic rights and liberties, the paper maintains. Individuals who self-isolate in situations of poverty, precarious housing, mental health challenges, abusive relationships or other vulnerabilities, face challenges that affect their security of the person. There are also broader effects on equality and human flourishing. “If contact tracing, enhanced by an app, reduces the need for restrictions in the form of self-isolation, it promotes other Charter rights and values (for example, security of the person), which must be balanced against the potential infringement of privacy rights.”

An electronic copy of the paper is available at