On-Call & Team Health Practical By Samson Tanimawo, PhD Published Sep 8, 2025 4 min read

Acknowledgment Time SLA

< 5 min for sev 1.

Standard targets

Sev 1: under 5 minutes. Customer-impacting incidents need immediate response. Pager fires; on-call acknowledges within 5 minutes.

Sev 2: under 15 minutes. Significant but bounded. Time to acknowledge is forgiving; time to action is what matters.

Sev 3: under 1 hour during business hours; next business day off-hours. Issues worth knowing; not worth waking up for.

Measuring it

Time from page sent to acknowledgement received. Not from incident detected; that conflates detection and response.

P95 against target, not median. The pages that take 30 minutes to acknowledge are where things go wrong, not the typical 2-minute responses.

Per-engineer view: identifies people struggling. Per-rotation view: identifies systemic issues. Per-time-of-day view: identifies night-shift gaps.

How to consistently hit

Multi-channel paging. Phone call, app push, SMS, voice escalation. Each channel can fail independently; redundancy is the safety net.

Backup on-call with explicit escalation policy. If primary doesn't ack in N minutes, secondary gets paged. Tested monthly.

Test the path quarterly. Synthetic pages verify the full chain. Surprises during real incidents are expensive.

MTTA trending up indicates degrading responsiveness. Causes: tool issues, on-call burnout, rotation understaffing.

MTTA trending down is usually positive. Watch for over-eager acks (acknowledging without engaging). Track time-to-action separately.

Per-time-of-day shows shift quality. Night shifts often higher MTTA than day; expected. Consistent night degradation suggests staffing gaps.

When MTTA is bad

First: paging tool reliability. Lost pages mean missed acknowledgements. The tool dashboard shows delivery rates.

Second: rotation health. Burnout, vacation gaps, off-hours coverage. Survey; staff up; address root causes.

Third: process. Routing accuracy. Severity classification quality. Often the MTTA target is reachable with better routing rather than more responsiveness.