Not to poo poo the app before it even gets going, but even even if you SOMEHOW manage to get 75% of smartphone users to run it, it would still give a reproduction number of 1.4 if lockdown were lifted.
— Hannah Fry (@FryRsquared) May 4, 2020
(anything above one is bad) Our paper here: https://t.co/DR2KiF5B59 pic.twitter.com/i8pn7JxRr5