Cause and Effect Diagram | Fishbone Diagram (Kaoru Ishikawa)

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Identifying and arranging the causes of an event or problem. Explanation of the Cause and Effect (Fishbone) Diagram of Kaoru Ishikawa. (1943)


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Kaoru Ishikawa Fishbone DiagramWhat is a Cause and Effect Diagram? Description

The Cause and Effect Diagram (Fishbone Diagram) from Japanese quality control statistician Kaoru Ishikawa is a graphical technique that can be used in teams to identify and arrange the causes of an event or problem or outcome. It graphically illustrates the hierarchical relationship between the causes according to their level of importance or detail and a given outcome. Also called: Ishikawa Diagram.

Origin of the Fishbone Diagram. History

The Fishbone Diagram was invented by Professor Kaoru Ishikawa of Tokyo University, a highly regarded Japanese expert in quality management. He first used it in 1943 to help explain to a group of engineers at Kawasaki Steel Works how a complex set of factors could be related to help understand a problem.

Usage of the Cause and Effect Diagram | Fishbone Diagram. Applications

  • Concentrating on a complex problem in a team effort. Compare: 8D Problem Solving
  • Identify all causes and the the root causes for a specific effect, problem, or condition.
  • Analyze and relate some of the interactions among the factors affecting a particular process or effect.
  • Enable corrective action.

Steps in creating an Ishikawa Diagram. Process

  1. Explain the purpose of the meeting. Then identify, and clearly state, and agree on the problem or effect to be analyzed.
  2. Position a whiteboard or flipchart so that everyone can see it. Draw a box containing the problem or effect on the right side of the diagram with a horizontal spine.

  3. Conduct a Brainstorming session. As a first draft, for the main branches you can use the following Categories:
    • Services industry: the 8 Ps: People, Product/Service, Price, Promotion, Policies, Processes, Procedures, Place/Plant/Technology.
    • Manufacturing: the 6 Ms: Manpower, Methods, Measurements, Machinery, Materials, Mother Nature (environment).
    • Use the above categories by asking for example: What are the People issues affecting/causing the problem?
  4. Identify the main causes contributing to the effect being studied. This could be done applying a Pareto Analysis (80/20 rule) or a Root Cause Analysis.

  5. These main causes become the labels for the sub branches of your diagram.

  6. For each major sub branch, identify other specific factors which may be the causes of the effect. Ask: Why is this cause happening?
  7. Identify increasingly more detailed levels of causes and continue organizing them under related causes or categories.
  8. Analyze the diagram.
  9. Act on the diagram. Remove the causes of the problem. Generic systematic approaches for this are the Deming Cycle or RACI.

Strengths the Cause and Effect Diagram. Benefits

  • Helps to find and consider all possible causes of the problem, rather than just the ones that are most obvious.
  • Helps to determine the root causes of a problem or quality characteristic in a structured way.
  • Encourages group participation and utilizes group knowledge of the process.
  • Helps to focus on the causes of the issue without resorting to complaints and irrelevant discussion.
  • Uses an orderly, easy-to-read format to diagram cause-and-effect relationships.
  • Increases knowledge of the process by helping everyone to learn more about the factors at work and how they relate.
  • Identifies areas for further study where there is a lack of sufficient information.

Limitations of the Ishikawa Diagram. Disadvantages

  • Not particularly useful for extremely complex problems, where many causes and many problems are interrelated.

Assumptions of the Fishbone Diagram. Conditions

  • A problem is composed of a limited number of causes, which are in turn also composed of sub causes.
  • Distinguishing these causes and sub causes is a useful first step to deal with the problem.

Book: Kaoru Ishikawa - Guide to Quality Control -

Cause and Effect Diagram (Fishbone Diagram) - Ishikawa Forum
  When Should we Use a Cause Effect Diagram?
In addition to the usage and application areas already mentioned in the summary, the Ishikawa Diagram can be used in the following situations:
- To study a particular problem and find the root cause of it;
- To identify areas of data collec...
  How to Apply Cause and Effect Analysis in a Processing Plant?
I work in a process plant. I'm always facing breakdowns of machinery or even small defects. People including myself tend to replace immediately the defective part, and restore the machine in service.
I know this is not as good as analyzing and f...
  Cause and Effect Diagram: Next Steps
It is well known that C&E analysis is a good tool for trouble shooting. My point is there can be many causes while drawing the C&E diagram. Once the diagram is complete how can one go to the root cause? Some people say the  
  Ishikawa System Limitations
The Ishikawa system is a practical, solid tool for solutions of the quantitative problems. But when getting into subjective or qualitative factors it is a very weak application because of the difficulty in the interpretation of the human facto...
  Approximate Main Cause
Cause-effect diagram is one of methods determining the approximate main cause not the exact one
Because it depends on the adequateness of are the suggested categories and consequentially, the reasons and sub-reasons....
  Understanding Demand and Failure Demand
I am an MSc student of Six Sigma for service. For my final project I am evaluating the benefits of DMAIC lean "systems thinking" in a call centre. This involves mapping waste at a high level, by understanding demand and failure demand (things ...
  The 4Ms Model to Name Ishikawa Main Causes
I checked the internet to find out who and when used the original 4Ms as names for the main cause categories (branches). Unfortunatelly I could not find it, even in papers referring to Ishikawa's book from 1982.
Maybe you know when and where thi...
  Ishikawa Process in Quality Control and Quality Management
Problem Analysis for quality control/management issues using the Ishikawa process has a high degree of applicability. Its a simple yet effective and is able to generate a fairly accurate solution. Highly recommended for quality improvement programmes...
  Determining the Relevance of a Problem with an Ishikawa Diagram
I use the fishbone to determine the relevance of a problem. On the upper side of the fishbone I put the positive characteristics (what are the benefits if the problem is solved). On the lower side the negative (what are the cost elements). I rate all...
  Complex Effect and Cause Relations
Note that Effects and Causes of organizational problems are often interlinked as when a child does not study and the mother scolds him. But the child thinks: because my mother is scolding me every time I don't study.
So we can both say that the ...
  Solution and Effect Diagram
There exists also an inverted Ishikawa Diagram, with the Solution on the left and a big arrow with branches pointing to the right. The branches show the consequences and effects of the solution. You can use it to show, discuss, analyze what the conse...

Cause and Effect Diagram (Fishbone Diagram) - Ishikawa Special Interest Group

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Best Practices - Cause and Effect Diagram (Fishbone Diagram) - Ishikawa Premium
  Six Sigma and Fishbone Diagram
Is there a relation between six-sigma and the fishbone diagram?...
  What is the Taguchi Principle?
Has anyone heard of the Taguchi principle and can you please explain what it is in simple terms? What are the benefits in logistics channels?...

Expert Tips - Cause and Effect Diagram (Fishbone Diagram) - Ishikawa Premium

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Resources - Cause and Effect Diagram (Fishbone Diagram) - Ishikawa Premium

Ishikawa Diagram

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- Kaoru Ishikawa - Basic Concept - 7 Causes, 5 M's, 4P's, 4S's - Aim of Method - Steps - Practical Examp...
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Example of Root Cause Analysis: The Jefferson Memorial

The stone of the Jefferson Memorial in Washington DC was deteriorating quickly. Using Root Cause Analysis Usage (application): Root Cause Analysis, RCA, 5 Whys, Ishikawa Diagram, Cause and Effect Analysis

Determining the Root Cause of a Problem

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1. Why determine Root Cause?
2. What is a Root Cause?
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Using the Whys Method

To solve a problem effectively, you need to drill down through the symptoms to the underlying cause. Sakichi Toyoda, one of the fathers of the Japanes...
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Creating a Fish Bone Diagram in Excel

In this tutorial you can learn how to make a Fish Bone Diagram using Excel....
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First Introduction to 8D Problem Solving and Root Cause Analysis

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Cause and Effect Diagram

Download and edit this 12manage PowerPoint graphic for limited personal, educational and business use. Republishing in intranets, websites, books, ma...
Usage (application): Cause and Effect Analysis


Cause Effect Diagram


Fishbone Diagram


Cause Effect Diagram


Fishbone Diagram


Cause Effect Diagram


Fishbone Diagram


Cause Effect Diagram


Fishbone Diagram

Compare with the Cause and Effect Diagram: 8D Problem Solving  |  Root Cause Analysis  |  Theory of Constraints  |  Dialectical Inquiry  |  Mind Mapping  |  Pyramid Principle  |  Delphi Method  |  Analogical Strategic Reasoning  |  Action Learning  |  Brainstorming  |  Six Thinking Hats  |  Kepner-Tregoe Matrix  |  RACI  |  Gantt Chart

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