[mercer]

I think what's worse is that I suspect the whole project won't be all that useful, and a drop in the bucket compared to society-wide (enforced) change in behavior.

From everything I've read, this kind of app 1) is only really useful if enough people actively use it, and 2) have serious issues with false positives because of inherent positional inaccuracy (or inability to be accurate without sucking battery).

In regards to 1, in my country at least, unless using the app would be mandatory, I know many more people who will refuse to use it or be too lazy to use it. And I'm pretty sure hell will freeze over before the government can make usage (and owning a smartphone) mandatory.

[rsynnott]

So, false positives may not matter in some conditions. Ireland is currently reporting anything from 5 to 30 cases per day, doing anything from 3000 to 10000 tests per day, and has capacity for at least 15000 tests per day. If the app doubles the number of tests being done and finds a few new cases, that's fine; it's still a lot better than NOT finding those cases.

These apps would, granted, be far less useful in places with major ongoing outbreaks and inadequate testing infrastructure; lockdowns should be used to bring numbers down to the level where this sort of thing is workable.

(1) is probably a greater problem. Ireland has about 30% uptake, which probably isn't enough.

[mercer]

Yeah, after I wrote my comment I figured that perhaps I overstated how useless the app would be. I imagine even with relatively low uptake it'll have /some/ effect. Even a little would help, I suppose.