Time-to-Repair
When this component breaks, how long does it take to restore? A sensor of maintainability measured in hours, not in subjective assessment.
Time-to-repair (MTTR) measures how long it takes to fix a failure, from detection to restoration. Long repair times indicate code that is difficult to understand, debug, or safely modify — even if you don’t know why it’s difficult.
Sensor properties
| Property | Value |
|---|---|
| Oracle strength | Medium — long repair time correlates with complexity |
| Independence | High — measured from incident records |
| Scope | Module-level |
| Feedback latency | Weeks |
| Actionability | Exploratory — shows where repair is slow |
| Type | Retrospective |
What it cannot detect
Time-to-repair conflates code difficulty with operational factors (on-call response time, deployment latency, test suite duration). A long repair time may not reflect code quality at all.