Advanced Level – Cross-Cutting
Mean Time to Detect (MTTD) – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
The average time between when a defect or incident is introduced and when it is detected.
In simple words
How long, on average, a bug lives in the system before someone notices it.
Exam tip
MTTD + MTTR are the core DevOps quality KPIs alongside DORA metrics.
Related terms
Practice this term in the ISTQB Mock Test
40 CTFL v4.0 questions, 60-minute timer, instant scoring and chapter-wise breakdown.
Practice in Mock Test