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There are SO MANY teams right now working on contact tracing apps that use bluetooth and GPS logging so they can alert you when you& #39;ve been in contact with someone that tests COVID-positive.
My hot take: they won& #39;t work. For my first-ever tweetstorm, I will tell you why. [1/n]
My hot take: they won& #39;t work. For my first-ever tweetstorm, I will tell you why. [1/n]
The effectiveness of contact tracing is a quadratic function of adoption. To trace contact between two people, they BOTH need to have a specific contact tracing app installed (and bluetooth/gps needs to be on, and the phones can& #39;t be buried too deep in a bag, and and and..) [2/n]
The best team that has implemented contact tracing so far is Singapore. Open-source, privacy preserving, and marketed by the government. It saw record-breaking downloads for a government app. Today, 1 in 6 Singaporeans have it installed. Pretty good, right? [3/n]
Not good enough. The chances of two people in contact having the app installed is (1/6) * (1/6) = less than 3%. And that& #39;s an app sponsored, sanctioned, and pushed by the government. I think an app from MIT/Stanford/YC/whatever is going to see even lower adoption. [4/n]
Worse: on iOS, it only works if the phone is unlocked and the app is in the foreground. WHAT! Yes: the government tells you to turn on the app and flip your phone upside down. Even 3% is highly optimistic. [5/n]
![Worse: on iOS, it only works if the phone is unlocked and the app is in the foreground. WHAT! Yes: the government tells you to turn on the app and flip your phone upside down. Even 3% is highly optimistic. [5/n]](https://pbs.twimg.com/media/EVOA5-gU0AE5BhE.png "Worse: on iOS, it only works if the phone is unlocked and the app is in the foreground. WHAT! Yes: the government tells you to turn on the app and flip your phone upside down. Even 3% is highly optimistic. [5/n]")
![Worse: on iOS, it only works if the phone is unlocked and the app is in the foreground. WHAT! Yes: the government tells you to turn on the app and flip your phone upside down. Even 3% is highly optimistic. [5/n]](https://pbs.twimg.com/media/EVOA5-dVAAE_M-c.png "Worse: on iOS, it only works if the phone is unlocked and the app is in the foreground. WHAT! Yes: the government tells you to turn on the app and flip your phone upside down. Even 3% is highly optimistic. [5/n]")
Contact tracing is nerd-bait. So many scrappy teams are working towards this promise to solve the virus with an app. Only an official effort, led by Apple+Google or maybe FB and then forced upon users, can reach the critical mass needed to make contact tracing viable. [6/n]
Ok so, I bet one of those three companies will release a contact tracing app by the end of May, and the internet will probably be angry and scared of it, but maybe we give it a chance so we can finally go outside again? [7/fin]
