@RafaIsTheKingOfClay
We were getting under 1000 positives on 150000 tests a day last summer. If that’s a recent number, then SAGE might need to redo their calculations. I suspect the FPR is quite a lot lower than 0.8%
I posted a link earlier in the thread from the autumn where an FPR of 0.8% was being quoted in an article explaining why false positives weren't a significant issue. However, as you say, our low cases over the summer suggests this rate looks like an overstatement. A pp upthread mentioned that David Spiegelhalter suggests a FPR of 0.05% for PCR tests, for example.
However, a difference from where we were in the summer is the rise in random mass testing via lateral flow tests. I also posted this link earlier, which gives a FPR of 0.32% for lateral flow tests (clearly, the false negatives are still a much much bigger issue with these tests).
fullfact.org/health/lateral-flow-test/
I don't know if there have been any further advances on calculating the FPR for lateral flow tests since this article was published? Today, the government are floating the idea of sending out 400k lateral flow tests daily for random testing purposes. 0.32% of 400k is 1,280 cases. If the 0.32% is a reasonable figure, then I can't see how this issue can be completely disregarded if we do start random mass testing on a major scale.