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1/x #Covid19 apps. There is theory and there is practice. Here are a few of my concerns (and no, #privacy is not one of them). 
#CoronaApp
#CoronaApp
2/x Any app only works if people who have contracted the #CoronaVirus will actually upload their positive status in the app. If people donât trust app, they may choose not to upload their status, which would make the app one giant placebo. #CoronaApp
3/x One only knows about a positive status if one is tested or visits a doctor. Currently, we donât test enough. And we already know of many cases where people have died without even having seen a doctor because nobody suspected #Covid19. Data quality is suboptimal. #CoronaApp
4/x And then there is irrational human behavior. Unfortunately, there will be people who âf*ck the systemâ by uploading a false positive status just to scare people into two weeks quarantine. #CoronaApp
5/x Also, the app only works if people actually go into quarantine or get tested after an alert by the app. That may happen the 1st time, and the 2nd, but maybe not the 3rd, 4th or 5th time. So the #CoronaApp may have limited effectiveness in time.
6/x The higher the number of false positives, the more likely it is people will start disregarding the app. However, a high rate of false negatives is even worse, because that undermines the entire raison dâetre of the #CoronaApp.
7/x There may be social effects: Even if the #CoronaApp is not mandatory by law, carrying the app may be socially mandatory. Employers and owners of publicly accessible places, like restaurants or supermarkets may want to know. Effectively turning society into Little Sister.
8/x Focus on #privacy and security, although important, risks losing sight of all other negative effects of the #CoronaApp.
