Hacker News new | ask | show | jobs
by prepend 2281 days ago
Isn’t false negative specificity and false positive sensitivity?

https://en.wikipedia.org/wiki/Sensitivity_and_specificity

1 comments

No, sensitivity is TPs / all positives (detected TP and FN). It’s the green half of the diagram in your link. The language is very easy to get tripped up by though. :)
I think I’m getting tripped by false positive, true positive.

A test with high sensitivity will have a low false positive rate.

A test with high specificity will have a low false negative.

So having a test with high sensitivity but low specificity will result in trust in the positives, but not trust in the negatives?

For me it’s easier to think of sensitivity as being “sensitive to the true positive” without saying much about false positive or negative.

A sensitive test will catch many positive cases. It may or may not have false positives though, eg a test that’s always gives the right answer vs a test that always returns positive no matter what.

A specific test will give you few positive results when the true answer is negative. You could use it to rule something out. One test might say “patient has A or B condition”, and a second test with high specificity may then rule out A or B, leaving B or A, respectively, as the probable condition.