5 whys pattern
Ask 'why?' five times in succession to get from a surface symptom to a contributing cause. Originated at Toyota for manufacturing defects. In software it's a useful heuristic but not a complete root-cause analysis — incidents in complex systems usually have multiple contributing factors, not a single linear chain.
Ask 'why?' five times in succession to get from a surface symptom to a contributing cause. Originated at Toyota for manufacturing defects. In software it's a useful heuristic but not a complete root-cause analysis — incidents in complex systems usually have multiple contributing factors, not a single linear chain.
symptoms
- incident reports that stop at the immediate trigger
- recurring incidents with the same surface symptom
- no shared understanding of what actually went wrong
causes
- stopping at the first plausible-sounding cause
- investigating under time pressure
- analyst settles for an answer that absolves their team
fixes
- go beyond five if needed; stop when 'why' becomes meaningless
- treat it as a starting heuristic, not a complete RCA — pair with contributing-factors analysis
- do it as a group so multiple perspectives surface
you might say
- walk the five whys
- do a 5-whys
- one more why