[arrrg]

False positives do matter. However, we are currently at about 300 new cases per day in Germany. So how much do they matter, really?

If everyone of those has the app installed and has, on average, 100 registered contacts (so that’s about 98 false positives, if we assume that on average two of those lead to infections) that’s about 30,000 people being told to isolate every day.

If they are told to isolate for one week (should be sufficient, on balance) that’s around 200,000 people isolated at any one point in time.

If only 50% have the app installed that’s down to 100,000 people.

Sounds high but ok to me. Given how active the infection currently is in Germany I wouldn’t want false positives be higher than that – but somewhere in that high ballpark sounds fine to me.