Is Contact Tracing Dumb? False Positives, Loss of Trust, and an Uncertain Path Back to Normalcy

There has been so much hype about contact tracing technology and how it will be the key to reopening the country. Google and Apple, for example, are building a system to track contact between people who might spread the disease. The idea is simple: since Bluetooth is constantly scanning for other devices, your phone can use wireless signals to see who you’ve been near. Somebody who gets a positive diagnosis can tell the app, which will inform everyone else who has been in proximity to alert them about risks of possible transmission.

So basically, by using Bluetooth technology, our phones can exchange information on who you’ve been in contact with, and if you’ve been in the proximity of someone with Covid, your phone can alert you. This theoretically does away people’s worry about mass surveillance because no location or personal data are actually being recorded by the contact-tracing app – only bluetooth signals. But can this app live up to its promises?

One study suggests that if contact tracers successfully detected 90% of symptomatic cases and reached 90% of their contacts it could reduce transmissions by more than 45%. But this will be difficult in regions still grappling with lots of new infections. Also, if not everyone in a given community uses the app, the efficacy will be significantly reduced. False positives and false negatives will also be significant challenges, and if the app falsely notifies people of their status, it could let the public lose faith in the technology and trust in public health officials.

This interview is an excerpt from our last interview with Mr. Bruce Schneier – public-interest technologist and author of "Click Here to Kill Everybody" – and he explains why contact tracing technology is "dumb" and why we would need to resort to the old-fashioned testing and tracing if we were to go back to normal.

Bruce Schneier is a public-interest technologist and the author of over one dozen books – including his latest, "Click Here to Kill Everybody." He has also written hundreds of articles, essays, and academic papers. His influential newsletter "Crypto-Gram" and his blog "Schneier on Security" are read by over 250,000 people. He is a fellow at the Berkman Klein Center for Internet & Society at Harvard University; a Lecturer in Public Policy at the Harvard Kennedy School; a board member of the Electronic Frontier Foundation, AccessNow, and the Tor Project.

Bruce Schneier