Mean Time To Repair
Mean Time To Repair (MTTR) is a maintainability metric that measures the average time required to restore a failed system to normal operation.
“The average time a component or system will take to recover from a failure.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Mean Time To Repair?
MTTR includes diagnosing the problem, repairing the fault, verifying the fix, and returning the system to service.
Recovery measurement: Lower MTTR indicates faster restoration.
Operational impact: Faster repairs improve system availability.
Maintenance planning: Helps evaluate support effectiveness.
Real World Example
A regulated product team is preparing a release where Mean time to repair appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Mean time to repair as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Mean time to repair and similar ideas.
The page becomes useful in practice because Mean time to repair is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Mean time to repair in the context of ISTQB terminology?
Question 2
A tester needs to explain Mean time to repair to a non‑technical stakeholder. Which approach is MOST appropriate?
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