MTTD (Mean Time to Detect) measures the average time between when a failure starts and when your team becomes aware of it. It sits before MTTA and MTTR in the incident timeline: you cannot acknowledge or resolve what you have not yet detected. Teams that track MTTD with modern incident management software close the gap between silent failure and first human response.
Why MTTD Matters
- Silent Failures Are Expensive: Customers often feel pain before dashboards do; a long MTTD means revenue and trust erode before anyone is paged.
- It Caps Every Downstream Metric: MTTA and MTTR cannot improve past the detection lag — MTTD is the floor of your response timeline.
- It Exposes Monitoring Gaps: Rising MTTD usually points to missing SLIs, weak synthetic checks, or alerts that fire too late.
How MTTD Relates to MTTA and MTTR
- MTTD: Time from failure start → detection (monitoring/alerting).
- MTTA: Time from detection → human acknowledgment (paging and on-call readiness).
- MTTR: Time from detection (or acknowledgment) → full resolution (engineering response).
Best Practices for Lowering MTTD
- Alert on User-Centric SLIs: Prefer checkout success rate or API error rate over CPU alone.
- Cover Blind Spots: Combine infrastructure metrics with synthetic uptime checks and customer-facing signals.
- Route Detections Fast: Once monitoring fires, push the signal into your incident platform without manual ticket creation.
The All Quiet Bridge
All Quiet shortens the path from detection to action. When your monitoring stack fires, webhooks create an incident instantly and page the right on-call engineer through multi-channel alerting. You keep MTTD low by catching failures early — and All Quiet keeps the next seconds from becoming minutes of silence.