It wasn't entirely clear from the article, but I assumed that the false positive rate referred to the ratio of people with matching search queries, not of all B

It wasn't entirely clear from the article, but I assumed that the false positive rate referred to the ratio of people with matching search queries, not of all Bing users. In that case the absolute number of false positives would be much lower. If that's true, how did they have enough real positives to measure such a low false positive rate? Also, the detection of 5% to 15% of cases would seem to me to refer to only Bing users; I doubt they're claiming to be able to detect 5-15% of all cases of pancreatic cancer. Yeah, I'm being dumb, there's no way that percentage is out of all cases!