Quote:
Originally Posted by blueash
Nice to see you read the study. I really cannot speak to the question of why the Canadian study had a low positivity rate other than to say that Canada has been extremely vigorous, or perhaps vigourous, in quarantine, masking, distancing, and convincing its citizens to take Covid seriously. The study was done in businesses on healthy persons. This did not involve people being tested because they were ill. Most of our positive Covid tests are on people with some symptoms or a defined exposure.
Secondly, as you read the study you already know how the authors explained the 42% figure, which you cite but don't explain. While the tests were done in several hundred locations, 60% of the false positives came from just 2 testing locations, from a single manufacturer and a single lot which led the authors to believe it was a faulty batch of tests. If you throw out the bad batch, which we should not when looking at data as it happens, then the rate of false positives falls to 200 out of nearly a million.
For those interested in reading the study... HERE |
I saw that, and the researchers believed that 278 of the false positives were related to faulty tests. But then, we have to subtract 278 from both the numerator and denominator (462-278=184/1322-278=1056) which yields a 17.4% false positive rate----you still can't use 900,000 as the denominator. So, throwing out the tests the researchers thought were defective, there's still a 1 in 6 chance that your positive home test is really negative.