Mean Time To Repair (MTTR) represents the average time taken to put a defective component or system back in working order. It is a measure of the maintainability of a system and predicts the average amount of time required to get the system to work again in case of a failure.
Consumer industries often recognize the importance of the customer perspective, and may use alternative names and definitions for this ‘time to fix’ parameter, for example, utility companies may refer to the out-of-service restoration interval.