3 ms·
This is not a question of mindset, it's a question of statistics when you're trying to identify anything that is rare. Take prostate cancer as an example. It's
by elbasti 5y ago
This is not a question of mindset, it's a question of statistics when you're trying to identify anything that is rare.
Take prostate cancer as an example. It's a relatively common cancer, with an incidence of .1% [0].
If you have an _incredible_ screening test with a 99% specificity (ie, 1% false positive rate), then:
If you test 100,000 people, you will correctly identify 100 people with cancer, and misdiagnose one thousand people as false positives.
There are consequences to having a false positive: unnecessary interventions, surgery "just to be safe", stress, etc.
This is why you limit testing to populations that have a higher probability of being ill (namely, show some sort of symptom).
Now imagine being tested for 100 things: the odds of coming up with a false positive for something start to approach 1!
- captainmuon 5y agoBut the tests are not binary sick or healty. If your test gets more sensitive, then you have to shift the, say, PSA value that you use for a diagnosis. I really hope that false positives become a regular thing. For one it shows that the tests are working according to statistics. Second, getting comfortable with false positives means that you can more easily hold off treatment, if in your specific scenario the treatment is not beneficial - think an old test that doesn't find the cancer plus a new test that does; and the new test is shown to lead to overtreatment. We need to learn when to hold on and not to treat. And third, if testing for 10 things will find something that you don't want to know and harm your psyche, when you test for 100 things you will have almost certainty that there is a false positive and this can give you back some of the "blissfull ignorance" I believe (while the doctor can still give you the statistically best treatment).