2. Dr. Kaoru Ishikawa
• Graduated from University of
Tokyo with an engineering degree in
applied chemistry.
• Worked as a naval technical officer
from 1939-1941.
• Worked at the Nissan Liquid Fuel
Company from 1941-1947.
• Started his academic career as an
associate professor at the University of
Tokyo in 1947.
• Joined the Japanese Union of
Scientists and Engineers (JUSE)
quality control research group in 1949.
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3. Ishikawa diagram
• Ishikawa also called as fishbone diagrams,
herringbone diagrams, cause-and-effect diagrams.
• Brainstorming tool used to identify potential root
causes to problems.
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4. Objective
• Determining the root causes of a problem.
• Focusing on a specific issue without resorting to
complaints and irrelevant discussion.
• Identifying areas where there is a lack of data.
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5. General Cause
• All causes are listed.
Root Cause
• Major cause is analysed by investigating the sub-
cause and its impacts on major cause.
Process Analysis
• Listing the causes in the sequential order.
• Flow diagram is created.
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6. Categories
Causes in a typical diagram are normally grouped into
categories, the main ones are
44S
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11. Benefits
• Helps determine root causes.
• Encourages group participation.
• Uses an orderly, easy-to-read format to diagram cause
and effect relationships.
• Indicates possible causes of variation.
• Increases knowledge of the process by helping
everyone to learn more about the factors at work and
how they relate.
• Identifies areas for collecting data.
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12. Drawbacks
• Not used for Complex problems.
• Are based on opinion rather than evidence.
• Assumed that a problem is composed of limited
number of causes.
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