What do you want to call the population of positives, if not P? What do you think the P in TP and FP refers to?

Also, why are you creating a chat thread on Hacker News with a plea to delete a page on Wikipedia?

TP + FN means true positives plus false negatives, that is the number of deseased people. P should be the number of people that gives positive in the test, since TP means true positive in that sense.

Also TP + FN = Prevalence of the desease, but using P for prevalence and for positive creates a lot of confusion in a wikipedia page to explain a concept.

My plea is that I don't want people to get confused. On top of it there is a warning on that page of wikipedia: This article may be too technical for most readers to understand. I couldn't understand why they used that notation. So I ask to delete that page because is going to confuse people.

> Also TP + FN = Prevalence of the d[i]sease, but using P for prevalence and for positive creates a lot of confusion

Nobody's using P for prevalence. It's being used for positive. Take a look at the table.

> that is the number of d[i]seased people

Yes, that is what "positive" means. (In the context of a test for disease.)

That Wikipedia page has a corresponding "Talk" page. Go discuss it there.

It's not my area so I have to ask:

1) Is P=TP+FN the standard notation in the area?

2) Is that notation confusing to people outside the area?

3) How is TP+FP called in that area?