5 Whys

The 5 Whys problem-solving technique is used to dig for the root cause of a condition by asking “why?” at least five consecutive times. As the answer to each “why” question is provided, the next “why” is asked in a continuous cycle until the base problem is found.


The 5 Whys technique helps to determine the root cause of a problem, such as delays in the schedule. To support continuous improvement, problems should not simply be resolved, but the reason(s) for the problem should be addressed so the error does not happen again.

By understanding the root cause of an issue, the team can uncover processes that are not working correctly, discern where planning was insufficient, or determine if different resources or tools are needed to perform a task more effectively.

5 Whys Problem Solving

How Visual Management Works

  • Why are we behind schedule? The excavator broke down.
  • Why? The battery was dead.
  • Why? The alternator gave out.
  • Why? The alternator belt broke.
  • Why? The equipment wasn’t maintained according to the recommended service schedule.

Best Practices

  • It is most effective when used to solve simple to moderately challenging issues.
  • For complex problems, it is best to use 5 Whys in conjunction with other problem solving methods since there are often multiple causes.
  • The success of the method relies on the skill of the facilitator and the people involved.


The 5 Whys method follows a very simple process.

First, invite people who are familiar with the issue to the meeting. Select a facilitator to lead the discussion, ask the 5 Whys, and keep the team focused on the issue at hand. Develop a clear and concise problem statement after discussing the problem with your team. Ask “why” as many times as needed until the team identifies the root cause of the initial problem. By identifying one true root cause, discuss what countermeasures can be taken to prevent the issue from happening again.


  • Include people with practical experience on the issue.
  • Use paper or whiteboard instead of computers.
  • Write down the problem and make sure that all people understand it.
  • Pay attention to the logic of cause-and-effect relationship.


  • Forget that not all problems have a single root cause. If you want to uncover multiple root causes, the method must be repeated asking a different sequence of questions each time.

Business Drivers

  • Help detect and eliminate organizational issues.
  • Identify the underlying cause of a problem.
  • Help to identify a sustainable, incremental solution to resolve the issue.


  • Enhance team morale among employees.
  • Help avoid iteration of failures.
  • Encourages team members to share ideas for continuous improvement.
5 Whys Attributes

 Complementary Methods

5 Whys problem solving is supportive of many Lean methods, such as: