Q. Explain Predictive validity?

Predictive validity: It is the potential of the model to predict future failure behaviour from present and past failure behaviour. This capability is important only when failure behaviour is changing. There are two universal ways of viewing predictive validity based on the two equivalent approaches to characterizing failure random process namely

1. The number of failure approach as well as

2. The failure time approach.

We can visually ensure the predictive validity by plotting the relative error against the normalised test time.