It's particularly bad because the baseline rate for cancer is pretty low. The incidence rate for men and women in the US from [1] is 439 per 100k. So taking int

It's particularly bad because the baseline rate for cancer is pretty low. The incidence rate for men and women in the US from [1] is 439 per 100k. So taking into account the baseline rate: Of 439 people with new cancers, 395 (90%) will get a positive result. Of 99,561 people without cancer, 9,956 (10%) will get a positive result. So a total of 10,351 people will get positive results, and 96% of those people will not have cancer, so a positive result means that you have (to a first approximation) a 4% chance of having cancer. If the breakdown from [2] is roughly accurate, taking into account no other risk factors, someone under 50 can expect an even lower baseline rate, the "true positive" rate of a test with 90% sensitivity would range from 0.1% in infants to 25% in people 90+ years of age. 1. https://www.cancer.gov/about-cancer/understanding/statistics https://www.cancer.gov/about-cancer/understanding/statistics 2. https://www.cancerresearchuk.org/health-professional/cancer-statistics/incidence/age#heading-Zero https://www.cancerresearchuk.org/health-professional/cancer-...