Reliability prediction

Simplistically, you can predict reliability by matching the measured reliability data to a known reliability model. You then extrapolate the model to the required level of reliability and observe when the required level of reliability will be reached (Figure 1). Therefore, testing and debugging must continue until that time.

Predicting system reliability from a reliability growth model has two main benefits:

• Planning of testing Given the current testing schedule, you can predict when testing will be completed. If this is after the planned delivery date for the system then you may have to deploy additional resources for testing and debugging to accelerate the rate of reliability growth.
• Customer negotiations Sometimes the reliability model shows that the growth of reliability is very slow and that a disproportionate amount of testing effort is required for relatively little benefit. It may be worth renegotiating the reliability requirements with the customer. Alternatively, it may be that the model predicts that the required reliability will probably never be reached. In this case, you will have to renegotiate the reliability requirements with the customer for the system.