RCA

What it is

Root Cause Analysis (RCA) investigates why an incident or recurring failure occurred and why existing controls did not prevent, detect, or limit it. In complex systems there is rarely one isolated root cause; useful analysis identifies interacting technical, process, organizational, and environmental contributors.

Typical evidence

Timelines, logs, traces, metrics, deployment records, configuration changes, dependency behavior, operator actions, and prior warnings help reconstruct what happened.

Useful techniques

• Five Whys for drilling into causal chains.
• Fault-tree analysis for combinations of necessary conditions.
• Causal graphs for interacting contributors.
• Change analysis for identifying relevant differences.
• Barrier analysis for controls that were absent or ineffective.

The output should drive specific, owned, prioritized actions. A blameless postmortem often contains the RCA, but the postmortem also records impact, response, communication, and follow-up governance.