Five Whys
Root cause, by asking why again and again
- PhaseFrame
- Group2 to 8 people
- Time20 minutes
- SettingRoom or remote
- ExecutivesYes
What it is
Five Whys is a root-cause method. The group states a problem as a fact, asks why it happens, and keeps asking why of each answer until it reaches a cause the team can act on. The technique is often attributed to Sakichi Toyoda and is widely associated with Toyota's production system.
When to use it
When a problem keeps coming back, or the team agrees on the symptom but not the cause.
When to skip it
When the problem has several independent causes. Use an Issue Tree or Fishbone.
How to run it
- 3 minWrite the problem as a fact, not an opinion.
- 12 minAsk "why does this happen?" and write the answer. Ask again of the answer. Continue until you reach a cause you can act on.
- 5 minCheck each link by reading backwards: "so that...".
About 20 minutes of method time. Add ten to fifteen minutes to open and close the session.
What to watch for
Stopping at a person ("they did not follow the process"). Asking why of a blame, not a cause. Treating five as a rule: stop when you reach something you can change.
The AI lens
At each step, ask whether data, process or ownership is the cause. A weak AI use case often has a data or ownership root cause.
What you leave with
A causal chain ending in a root cause the team can act on.
An example
Invoices are matched late. Why? Matching waits for approvals. Why? Approvers cannot see which invoices are waiting. Why? The data sits in two systems nobody owns. The chain ends at data ownership, which no matching tool would fix.
How it compares
Five Whys follows one chain of causes quickly. A Fishbone looks across categories of cause when the problem has several independent causes.
Related methods
Questions
What is Five Whys?
Five Whys is a root-cause method. The group states a problem as a fact, asks why it happens, and keeps asking why of each answer until it reaches a cause the team can act on. The technique is often attributed to Sakichi Toyoda and is widely associated with Toyota's production system.
When should I use Five Whys?
When a problem keeps coming back, or the team agrees on the symptom but not the cause.
How long does Five Whys take and how many people do I need?
Five Whys takes about 20 minutes and suits 2 to 8 people, plus a facilitator. Add ten to fifteen minutes to open and close the session.
How is Five Whys different from other methods?
Five Whys follows one chain of causes quickly. A Fishbone looks across categories of cause when the problem has several independent causes.
Can I run Five Whys remotely or with executives?
Yes. Five Whys works in the room or remotely. Remotely, put the canvas on a shared board in advance and write silently in the board, not in chat. Executives: Yes, works with executives present.