False positive rates should be understood by the doctors that recommend treatments, though. A doctor should be able to accurately tell a patient what the chance

False positive rates should be understood by the doctors that recommend treatments, though. A doctor should be able to accurately tell a patient what the chance is that they suffer from a disease based on a positive result from a test. Unfortunately, doctors tend to be terribly bad at this - they are generally quite inept at incorporating prior probabilities into the estimates, and assume that (for instance) if a test has only a 1% false positive rate, then that means a positive result means it's 99% certain that you have whatever it's testing for. If it's not immediately obvious why that's an idiotically dangerous assessment, then you need to think a bit about a rare disease that only shows up in 1 out of a million people, and then consider the 10,000 people that will test positive for it at a false positive rate of 1%. Don't worry, most doctors don't get this right at first, either, and they will happily suggest to all 10,000 of those people that they seek aggressive, even life-threatening treatment...the difference, of course, is that they're goddamn doctors, entrusted with keeping people alive, and they really ought to know better, whereas you're just some person on the Internet.