Youden index calculator
J = sensitivity + specificity − 1. Enter both as percentages from the same cutoff.
Questions
What is the Youden index?
Youden's J is sensitivity plus specificity, minus 1. It is 0 when the test is no better than chance and 1 when sensitivity and specificity are both perfect.
Does a higher Youden index mean a better cutoff?
It is one way to compare cutoffs when false positives and false negatives are treated as equally costly. If one error is worse, do not pick the cutoff by Youden's J alone.
Can Youden's J be negative?
Yes. A negative value means the test is worse than calling everyone negative or everyone positive. Check that sensitivity and specificity were not swapped.
Educational only. Not medical advice, not a regulatory determination, and not a substitute for qualified RA/QA, legal, clinical, or statistical counsel. Youden index does not submit to FDA, Notified Bodies, or IRBs.