Mean time to repair (MTTR)
The average time from defect detection to deployed fix — a measure of how quickly your team resolves confirmed issues.
// Formula
// About this metric
Mean time to repair (MTTR) for defects measures how quickly your team can go from "defect detected" to "fix deployed". Unlike MTTR for production incidents — which measures speed of service restoration — this MTTR measures the full repair cycle: triage, root cause analysis, fix implementation, code review, and deployment.
The formula is the average across a sample of defects of: (deploy-fix time − detection time). It is most meaningful when calculated separately by severity — your P1/critical MTTR and your P4/trivial MTTR will, and should, be very different numbers.
DORA research and Google's SRE Book provide the directional benchmarks used here: under 8 hours for fast teams, 8–48 hours for typical, and above 48 hours flagging slow repair throughput. These benchmarks blend pre-release and production defects, so treat them as directional rather than precise targets.
MTTR is affected by factors outside engineering control: waiting for sign-off, deployment windows, and downstream dependencies. A consistently high MTTR in a team that writes fixes quickly often points to process overhead rather than engineering capacity.
// Calculator
🧮 Calculator
// Benchmark
Source: Aggregated from DORA reports and Google SRE Book
Severity-weighted MTTR is usually more informative than raw MTTR — critical fixes shouldn't have the same target as low-priority defects.
// When to use this metric
Use MTTR to identify bottlenecks in your defect resolution process. If MTTR is high, break it down into phases — time-to-triage, time-to-fix, time-to-deploy — to locate where time is actually being lost.
Track MTTR by severity tier separately. A global average that looks acceptable can hide an unacceptable P1 MTTR masked by fast resolution of low-severity defects.
// Common pitfall
MTTR is easy to game by closing defects before the fix is verified, then reopening them as "new" defects. Watch for patterns of duplicate or reopened defects — they are a signal that MTTR is being measured at "closed", not at "verified fixed in production".