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Youden Index Calculator

Find the Youden J index from sensitivity and specificity.

Youden index (J) 0.75

Formula: J = sensitivity + specificity - 1

Step-by-step with your numbers:
1. Values used:
2. Sensitivity = 90 %
3. Specificity = 85 %
4.
5. Youden index (J) = 0.75
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The Youden index summarizes a diagnostic test's performance in one number.

The math behind it

J = sensitivity + specificity - 1, ranging from 0 (useless) to 1 (perfect).

Worked example

90% sensitivity, 85% specificity gives J = 0.75.

FAQ

What is it used for?

Choosing the optimal cutoff point on an ROC curve.

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