Root Cause Analysis
Ask 'why?' five times. Don't fix the symptom; find and fix the actual cause underneath.
Root cause analysis refuses to stop at symptoms. The Toyota Production System formalized this as the “Five Whys”: ask “why?” five times, and by the fifth answer you’ve usually found the structural origin of a failure. The wet floor is a symptom. The leaking pipe is an intermediate cause. The galvanic corrosion from mismatched metals is the root cause. Fixing the procurement process prevents all future galvanic corrosion issues, not just this one pipe. RCA is how you escape the cycle of symptom-fixing where the same class of bug keeps reappearing.
How It Works
State the symptom → ask why → state the cause → ask why again → repeat 4–5 levels deep until you reach a structural issue you can actually fix. Variants for complex systems: fishbone diagrams (categorize by people/process/technology) or fault tree analysis (map all causal chains as a logic tree).
Example
The jobs-apply CHRO audit surfaced incorrect enrichments for 189 job applications: the surface bug was a field-naming mismatch. Five Whys: wrong field name → AI used a different schema → validation checked computed data, not shipped data → the build process had no delivery gate. Root cause: no build validation. Fix: normalize-enrichment.ts + build validation gate. Prevents the entire class of error. Project context at Jobs Apply CHRO Audit.