5 Whys analysis
Asking "and why did that happen?" over and over to get from the visible symptom down to the root cause. Five is not a rule but a rough measure: once your answers start repeating themselves, you have hit bottom.
Register nowWhen to use it?
- Finding the real cause of a failure instead of treating the symptom.
- Post-incident reviews, where the point is the cause and not the culprit.
- Recording why a WBS task failed.
Step by step
- 1The menu at the top left switches between analyses in the same project, and lets you add, rename or delete one.
- 2Start with "Add problem" on the empty screen and state what happened in one sentence. There is also a ready-made example if you want to see the tool first.
- 3Ctrl-click a box to open a new "why" box under it. Write the answer there, then do the same on that box.
- 4When you cannot go deeper, Shift-click that box to create a root-cause box. Root-cause boxes take no children; the chain ends there.
- 5Right-click boxes to edit or delete them.
- 6An analysis holds a single main problem. To look into a second problem, open a new analysis from the menu at the top left.
Keyboard shortcuts (desktop)
Tips
- Starting a root cause analysis from a task in the work breakdown opens a separate analysis for that task; it does not overwrite the open one.
- A cause can have more than one answer; Ctrl-click the same box repeatedly to branch it.
- Ground every answer in something verifiable. "Carelessness" is not a root cause, it is an unanswered question.
- A WBS task marked as failed can be sent here as a problem straight from its right-click menu.
Worked example
Example: order confirmation emails are not arriving
Support has had the same complaint for three days. The first instinct is "let's switch email providers". Asking why five times shows the problem is somewhere else entirely.
Problem
- Customers are not receiving order confirmation emails.
The chain
- Why? The emails land in spam.
- Why? Our sending domain looks unverified.
- Why? A verification record is missing from the DNS settings.
- Why? It was not copied across when the server was migrated.
- Why? The migration checklist has no line for it.
Root cause
- The server migration checklist is incomplete.
Countermeasures
- Added the missing record (today's problem is fixed).
- Added domain verification to the migration checklist.
- Made the checklist independent of who runs the migration.
The first instinct was to change email provider: money spent, problem still there. The real root cause was one missing line in a checklist. Making that difference visible is the whole job of the five whys.
Frequently asked questions
What is 5 Whys analysis?
A technique for getting from the visible symptom to the actual cause by asking "why" repeatedly. It came out of Toyota. The point is to fix the thing that produces the symptom rather than the symptom itself, so the problem does not come back.
Why exactly five?
Five is a habit, not a rule. In practice most problems bottom out somewhere between the fourth and the sixth question. If you find it at the third, stop. If you are still nowhere at the seventh, you have probably defined the problem badly.
How do I know I have reached the root cause?
Two signs. The next "why" starts pointing at something outside your control, and you are confident that removing what you found would stop the problem recurring.
5 Whys or a fishbone diagram?
5 Whys follows a single chain downwards. A fishbone spreads the same problem across categories — people, method, machine, material, measurement, environment. If the cause seems to sit in one place, use 5 Whys. If it is scattered, draw the fishbone first.
Is it free?
Yes. Klarsti is free and ad-free right now, and you do not need an account to run a 5 Whys analysis.