# Prevalence threshold calculations error

I see on this page the formula for calculation of prevalence threshold:

Given also are following values on that page:

Sensitivity or TPR: 66.7%
Specificity or TNR: 91%


With these values, I am getting a prevalence threshold of 27%. However, it is mentioned as 19% on the wiki page.

Where is the error? Thanks for your help.

• You might want to take this up on the Wikipedia page. It's a real mess and could use some help! – whuber Jul 27 '20 at 13:51
• It will be great if you can put some points in an answer here because most things mentioned on that page are common beliefs. – rnso Jul 27 '20 at 17:21
• I am not claiming that page is wrong: it is just terribly laid out and confusing. (This calculation you quote does look incorrect, though.) – whuber Jul 27 '20 at 17:33