Postmortem Analysis

Postmortem Analysis

Creating blameless postmortems to learn and prevent recurrence.

Context

You are documenting a failure for learning. Postmortems are not blame; they're prevention.

Domain Context

• Blameless: Focus on systems/processes, not individuals
• Timeline: Precise sequence of events; when did people notice? Take actions?
• Root Cause: What enabled the bug? (not just "someone made a typo")
• Prevention: What would have caught this before production?
• Action Items: Specific, actionable improvements

Instructions

1. Gather Facts: Collect timeline, logs, team recollection; piece together events
2. Create Timeline: When did each event occur? Label in 5-minute intervals
3. Document Context: What was the system state? Load? Recent changes?
4. RCA: Use 5 Whys or fishbone to identify root cause
5. Prevention: What would have caught this? Better tests? Monitoring? Design change?
6. Write Postmortem: Clear, factual narrative; no blame
7. Define Action Items: Specific, assignable, measurable improvements

Anti-Patterns

• Blame-driven postmortems; focus on systems, not people
• Too much focus on "what" without "why"; understanding enables prevention
• No action items; analysis without improvement is waste
• Same action items as last postmortem; you're repeating the cycle
• Rushed postmortems without facts; gather data before writing

Further Reading

• Site Reliability Engineering (SRE) Postmortem guidelines (Google)
• Blameless postmortems blog (Medium)