Which of the following statements are true about Mean Time to Repair (MTTR)? Each correct answer represents a complete solution. Choose three.

A.
It is the total corrective maintenance time divided by the total number of corrective maintenance actions during a given period of time.

B.
It is the average time taken to repair a Configuration Item or IT Service after a failure.

C.
It represents the average time required to repair a failed component or device.

D.
It includes lead time for parts not readily available or other Administrative or Logistic Downtime (ALDT).

Explanation:
Mean Time to Repair (MTTR) is the average time taken to repair a Configuration Item or IT Service after a failure. It represents the average time required to repair a failed component or device. Expressed mathematically, it is the total corrective maintenance time divided by the total number of corrective maintenance actions during a given period of time. It generally does not include lead time for parts not readily available or other Administrative or Logistic Downtime (ALDT).

MTTR is often part of a maintenance contract, where a system whose MTTR is 24 hours is generally more valuable than for one of 7 days if mean time between failures is equal, because its Operational Availability is higher. MTTR is every now and then incorrectly used to mean Mean Time to Restore Service.