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IMIG Germany: Why, Why, Why, Why, Why – The 5-WHY-method

What is it?

The 5-WHY-method is a question asking tool used to explore the cause of relationships underlying a specific problem. The goal of applying the 5-WHY-method is to determine the root cause of a defect or problem. By repeatedly asking the question "why" you are able to find define the cause. Very often the underlying reason for a problem will lead you to the next question. After five times of asking “why” you might get the real reason for the defect or problem. Why five times? Five is a good rule of thumb and you´ve got five fingers on a hand.

How to use it?

1. Write and document the specific problem. Describe the defect/problem as good as possible. That helps to structure the 5 WHY-questions.

2. Ask the first "why" the problem exists or happens and document the answer.

3. Mostly the answer doesn't identify the root cause of the defect/problem. Then ask “why” again and document that answer.

4. Loopback to step 3 until the team is in agreement that the problem's root cause is identified. Often this may take more or less than five “whys”.

The 5-WHY-method can be used on its own or in connection with the Fishbone diagram (Ishikawa). The Fishbone diagram helps to explore all real causes in a single defect or problem. Of course, there can be more than one cause of a similar problem. At IMIG we use a template with a cause-effect diagram to visualizes and comprehend the similar steps in the 5 WHY-question rounds.

Example of a standardized fishbone diagram'
Fig. 1: Example of a standardized fishbone diagram; Source:

Fig. 2: Example of a customized IMIG template for the 5-Why method; Source: IMIG Knowledge Base
Fig. 2: Example of a customized IMIG template for the 5-Why method; Source: IMIG Knowledge Base

Lisa Lang
Lisa Lang
Junior Consultant I IMIG Germany

For further information please contact us either by mail: or by phone: +49 7152 928 460.

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