# What is the True Negative Rate?

The True Negative Rate (Specificity, Selectivity) is a performance metric that measures the probability that your model will predict *negative *when the true value is *negative*.

- It is closely related to the True Positive Rate, which is completely analogous.
- The False Positive Rate and the True Negative Rate sum up to 1.
- The True Negative Rate is the answer to the following question:
**“If the true value is negative, what share did my model predict correctly?”** - The True Negative Rate is calculated as follows:

\frac{TN}{TN+FP} = \frac{TN}{N} = 1 - FPR