The Fishbone Diagram: Origins and Modern Applications

Understanding the root causes of problems is an important aspect of a continuous improvement culture. To identify the causes and close performance gaps, there are many tools and techniques available. One practical tool for brainstorming the potential causes of performance gaps is Fishbone Diagram, also known as the Ishikawa Cause and Effect Diagram.

The fishbone is a visualization tool created by Dr. Kaoru Ishikawa in the 1940s. Revolutionary in its day, many formal institutions use the Fishbone as a root cause analysis methodology.  However, to be effective, the Fishbone must be combined with the 5-Whys (a Socratic questioning technique). And even then, the Fishbone rapidly becomes unwieldy with any level of complexity and is not an effective root cause analysis tool.

In this blog post, we will explain the Fishbone Diagram, exploring its modern applications and its limitations. Also, how BlueDragon IPS uses the best elements of the fishbone while eliminating its unwieldy structure.

Key Takeaways:

  • Origins: The fishbone diagram was invented in the 1940s by Dr. Kaoru Ishikawa, a Japanese quality control expert, to help employees avoid addressing only the symptoms of larger problems.
  • What is the Fishbone: The fishbone diagram, also known as the Ishikawa cause and effect diagram, is a tool used for brainstorming the potential causes of a problem by looking at the problem from different perspectives.
  • Modern Applications: The fishbone diagram can be used to brainstorm the possible causes of less significant and less complex problems.
  • Limitations: The fishbone diagram is not rigorous enough to be used as a root cause analysis tool. It also becomes increasingly difficult to draw and interpret for more complex issues.

Fundamentals of the Fishbone Diagram

Origins of the Fishbone Diagram

For decades, the Ishikawa Diagram has been a staple in quality management. Developed by Dr. Kaoru Ishikawa, a renowned quality management expert, this tool has been instrumental in helping teams to analyze problems from different perspectives or categories, which form the bones of a fishbone.  With its structured and visual approach, the Ishikawa Diagram was revolutionary in its day.


The Purpose of the fishbone diagram is to provide a visual tool for conducting a structured brainstorming session of a problem, failure or event, and identifying the potential causes.  It is not a useful tool for conducting root cause analysis for complex issues, which require much more rigor than the fishbone can offer.  The fishbone is best used for low complexity, low significance issues or events.


  • Demonstrates how to capture cause and effect relationships.
  • Makes us look at a problem from multiple angles (perspectives).
  • Can be expanded to include more themes.


  • Can quickly get complex, making it a poor causal analysis tool for anything more than the simplest of issues.
  • Difficult to visually identify the root causes and contributing factors on even simple issues (even with color coding).
  • Very difficult to draw a Fishbone with more than just a few Why Staircases.

The Bones on the Fishbone Diagram

There are a number of pre-established themes that have proven to be good starting points:

  1. Themes used in operating and chemical plants: Man, Method, Machines, Materials, Measurement, Environment
  2. The McKinsey 7S Framework: Strategy, Structure, Systems, Shared Values, Skills, Style and Staff
  3. The 4Ps of Marketing: Product, Place, Price, and Promotion
  4. The 8Ms Used in Manufacturing: Machine, Method, Material, Man Power, Measurement, Environment, Management/Money, Maintenance
  5. The 8 Ps used in Service Industry: Product/Service, Price, Place, Promotion, People, Process, Productivity & Quality, Physical Evidence
  6. The 4Ss used in Service Industry: Surroundings, Suppliers, Systems, Skills

Constructing a Fishbone Diagram

  1. Identify the Problem Statement: One of the initial steps in constructing a fishbone diagram is to identify the problem statement, also known as the effect. This statement is typically written at the center right of the diagram, surrounded by a box, with a horizontal arrow pointing towards it. This clear articulation of the issue serves as the focal point for the root cause analysis process.
  2. Establish the BONES on the Fishbone: With the problem statement established, the next step involves determining the major categories of causes. A systematic approach to categorizing causes not only aids in organizing the brainstorming session but also ensures a thorough examination of all potential factors. For example: 
    1. Man, methods, machines, materials, measurement, and environment,
    2. Strategy, Structure, Systems, Shared Values, Skills, Style and Staff
    3. Product, Place, Price, and Promotion
  3. Brainstorming potential causes: Diagramming potential causes follows the establishment of major categories in the fishbone diagram. Teams are encouraged to brainstorm all possible causes of the problem, asking ‘why does this happen?’ to generate ideas systematically.
  4. Conducting Cause and Effect Analysis: Continue to ask WHY questions to identify the deeper-seated causes, leading to a more comprehensive understanding of the underlying issues contributing to the problem statement.

Engaging in a thorough brainstorming session is crucial to uncovering all potential causes of the identified problem. The fishbone diagram’s hierarchical structure allows teams to probe deeper into the root causes by continuously asking ‘why?’ and exploring various layers of causality.  However, the overall construct makes it very difficult to identify the root causes of a problem. 


How BlueDragon IPS Modernized the Fishbone Diagram

The true value of the fishbone diagram is that it prompts us to analyze a problem from different perspectives (themes or bones).  The concept fits in very well with the BlueDragon IPS holistic approach to root cause analysis. So it was very important that we keep the best element of the fishbone, which are the bones themselves (or themes).

If we want to increase the level of rigor in our analysis, we can expand the number of themes we use to attack the problem.  However, the structure of the fishbone is not practical so it was modified in BlueDragon IPS to a modern interpretation.  The bones became themes and the themes are how we group lines of inquiry questions, but we stack those questions and their responses in a vertical manner.

Here is the modern representation of the problem statement and the themes that were once the bones on the fishbone. The cause and effect analysis is much easier to draw and interpret with this format.


The fishbone diagram, also known as the Ishikawa diagram or cause-and-effect diagram, is a useful tool for brainstorming and visualizing the potential causes of a problem from various perspectives, with each “bone” of the diagram representing a different category of causes. However, the fishbone diagram can become unwieldy and less effective when dealing with more complex problems that involve numerous interrelated factors.

To address this limitation, the BlueDragon Integrated Problem-Solving (IPS) methodology has modernized the fishbone diagram, retaining its core structure while introducing enhancements that make it more suitable for comprehensive causal analysis, using a more organized layout that facilitates the grouping of lines of inquiry questions under the themes, and makes the cause and effect analysis much more effective to help with the identification of root causes and the development of targeted solutions.


About the Author:

Rob De La EspriellaBD3, CEO and Founder, BlueDragon IPS

Deming Prize winning team member and pioneering Nuclear Quality Assurance expert Rob De La Espriella draws from four decades of experience in the commercial nuclear power sector and the nuclear weapons complex to offer deep insights into Root Cause Analysis and Total Quality Management. Rob is a leading expert in solving complex human-centric problems in our modern work environments, and has re-defined how organizations solve complex problems with the BlueDragon Integrated Problem-solving System (IPS), the first universal problem-solving system that can be applied to all regulated industries.  Rob is a former Navy nuclear submarine officer, a decorated Resident Inspector with the US Nuclear Regulatory Commission, and a senior manager at nuclear plants.  In 2023, he was accepted into the Forbes Business Council as a Forbes contributor.

© 2024 DLE Technical Services, LLC. All rights reserved.

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