# What is the Positive Predictive Value?

Given a *positive* prediction, the **Positive Predictive Value** (PPV) is the performance metric that tells you the probability that the true value is *positive*.

- It is closely related to the Negative Predictive Value, which is completely analogous.
- The complement of the Positive Predictive Value is the False Discovery Rat. They sum up to 1.
- The Positive Predictive Value gives you the answer to the question:
**“If the prediction is positive, what share of my prediction is truly positive?”** - The Positive Predictive Value is calculated as follows: