Fish bone/ Ishikawa diagram is named after Kaoru Ishikawa, a quality expert from Japan.It is a tool used to visualize, identify and classify possible causes of problems in process, product or services. Also known as cause effect diagram.Using this tool root cause of problems can be identified.

Following are the steps:

1. Identify a problem (effect) with a list of potential causes and Write the effect.

3. Identify major causes of the problem, which become “big branches”. 

4. Fill in the “small branches” with subcauses of each major cause until the lowest-level

subcause is identified.

5. Review the completed diagram with the work process to verify that these causes (factors) do affect the problem being resolved.

6. Work on the most important causes first. 

7. Verify the root causes by collecting appropriate data (sampling) to validate a

relationship to the problem.

8. Continue this process to identify all causes, and, ultimately the root cause.


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