Protocol
Follow the why-chain until the cause becomes changeable
Do not stop at a label that merely renames the event.
When it fits
- The immediate explanation is a label such as human error, missed step, bad data or process deviation.
When to avoid it
- Five Whys is a prompt for inquiry, not a guarantee of one root cause. Complex failures commonly have interacting causes.
Why it matters
Ask why the observed event was possible, then ask why about the answer while the chain remains evidence-based. Stop when you reach a factor the system can change, when the chain branches, or when evidence runs out. Record branches instead of forcing one linear root cause.
Steps
- Is this answer more than a label?
- What evidence supports the next link?
- Did the chain split into multiple contributors?
- Is the current factor changeable?
- Are we now guessing?
An example
Wrong field mapped → template used an old label → template had no version check → add a version gate at upload.
Check your result
The final factor suggests a concrete control and each causal link has evidence or is marked as a hypothesis.
Keep this limit in mind
- Five Whys is a prompt for inquiry, not a guarantee of one root cause. Complex failures commonly have interacting causes.
Connected ideas
AlternativeFan possible causes out before narrowing them
Evidence and sources
Modern RCA guidance emphasizes system-level contributing factors and sustainable corrective actions rather than stopping at individual blame or documentation.
AHRQ discusses healthcare safety. The corpus transfers the system-design logic cautiously to ordinary work.
The Evolution of Root Cause Analysis · Introduction; RCA2; action hierarchy discussion
Five Whys is used in RCA2 to extend a causal chain beyond an immediate event description.
Repeated 'why' questions can oversimplify branching causes; answers still need evidence.
The Evolution of Root Cause Analysis · Discussion of event mapping and Five Whys