What I learned from an article of a major German newspaper is that in order to really estimate the quality of testing, two criteria are important: sensitivity a

What I learned from an article of a major German newspaper is that in order to really estimate the quality of testing, two criteria are important: sensitivity and specifity of the applied test. If the real infection rate is still low throughout the population, a random sampling will not lead to reliable results (you could also toss a coin). Although the article is in German, it is worth to have a look on the graphic in the middle of the page, it should be understandable. https://www.sueddeutsche.de/gesundheit/corona-test-antikoerper-1.4883631 https://www.sueddeutsche.de/gesundheit/corona-test-antikoerp...