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What 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

Explain the purpose of the meeting. Then identify, and clearly state, and agree on the problem or effect to be analyzed.
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.
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?
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.
These main causes become the labels for the sub branches of your diagram.
For each major sub branch, identify other specific factors which may be the causes of the effect. Ask: Why is this cause happening?
Identify increasingly more detailed levels of causes and continue organizing them under related causes or categories.
Analyze the diagram.
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 -

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Discussions about Cause and Effect Analysis.

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	Ishikawa System Limitations The Ishikawa system is a practical, solid tool for solutions of the quantitative problems. But when getting into subject (...)

	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 mot (...)

🔥	NEW 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 (...)

	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 (...)

	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. It (...)

	Only the Probable, Approximate Main Cause is Found! Cause-effect diagram is one of methods determining the approximate main cause not the exact one Because it depends on t (...)

	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). (...)

Best Practices about Cause and Effect Analysis

Here you find the most valuable discussions from the past.

🥇	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 drawi (...)

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🥉	Six Sigma and Fishbone Diagram Is there a relation between six-sigma and the fishbone diagram? (...)

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Expert Tips about Cause and Effect Analysis

Here you will find advices by experts.

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Information Sources about Cause and Effect Analysis

Here you will find powerpoints, videos, news, etc.

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Cause and Effect Diagram | Fishbone Diagram (Kaoru Ishikawa)