Good Postmortem vs Great
What separates.
Overview
The difference between a good postmortem and a great one is depth, not template adherence. Great postmortems carry detailed timelines, multi-cause analysis instead of single-root-cause framing, SMART action items, and system-level lessons that apply beyond the immediate incident. Good postmortems get checked off; great ones change how the organisation operates.
- Detail of timeline, depth of analysis, action-item quality. Three axes that separate good from great. All three matter.
- Detailed timeline. Per-minute granularity for SEV1 and SEV2. Reconstruction precision drives learning quality.
- Multi-cause analysis. Contributing factors, not single root cause. Reality is rarely one cause.
- SMART action items plus system-level lessons. Specific, measurable, achievable, relevant, time-bound; lessons that apply beyond this incident.
The approach
Three habits move postmortems from good to great: detailed per-minute timelines on high-severity incidents, multi-cause analysis that resists the single-root-cause temptation, SMART action items that survive the next planning cycle.
- Detailed timeline. Per-minute granularity for SEV1 and SEV2. Hours-only timelines lose the patterns that matter.
- Multi-cause analysis. Contributing factors named explicitly. Single-root-cause framing oversimplifies and underprotects.
- SMART action items. Per-action the SMART framing. Vague action items do not ship.
- System-level lessons plus documented standard. Per-postmortem the broad lesson; per-team the great-postmortem standard documented.
Why this compounds
Each great postmortem deposits durable organisational learning. Action items ship because they are specific; system-level lessons get reused; new engineers learn what excellent looks like by reading the archive.
- Learning improves. Great postmortems produce real institutional knowledge.
- Follow-through improves. SMART action items get done. Vague ones evaporate.
- Team scaling. Great postmortems teach new engineers what excellent analysis looks like.
- Year-one investment, year-two habit. First great postmortem is heavy lift. By the fifth, the standard is settled.