They were an ill conceived “great idea doomed to success”. Seemed like a great idea but in practice, they are likely not workable.

I have posted many items on this topic already.

  • They really do need mass adoption to have a meaningful impact. Even at 50% adoption, they could only detect 25% of potential contacts.
  • Due to their use of an unreliable signal strength metric, their reliability was dicey.
  • They incorrectly report contacts where there is no threat – such as a sick person sitting at a table outside Starbucks, while you are sitting on the opposite side of the window, inside Starbucks.
  • They do not detect contacts “across time”. Someone sits on a light rail seat, coughs, gets up and leaves. You then board, sit on the seat and touch it with your hands, contaminating your hands and later your face.
  • And many more problems.

Smart phone contact tracing apps, based on Bluetooth proximity detection, have largely vanished. Will they be back next month?