> sending nine out of ten people to the doctor That's not happening. Only a small number of people went to the doctor. Of that number, 9 out of 10 ended up not

> sending nine out of ten people to the doctor That's not happening. Only a small number of people went to the doctor. Of that number, 9 out of 10 ended up not being diagnosed with a (new) problem, but it seems that even some of them had related problems that were already diagnosed. Regardless, we don't know the false positive rate. It's not 90%. You need to know the number of negatives before you can calculate it.