Guide to understanding Ishikawa diagrams

What is an Ishikawa diagram?

An Ishikawa diagram is designed to show the potential causes of a specific event or process. It is commonly used in product development to brainstorm and outline the different steps within a given process, allocate resources, and determine whether quality control issues are likely to arise.

The diagram is named after its creator, Kaoru Ishikawa. Visually, the diagram's structure resembles the skeleton of a fish. The ribs represent the causes of an event, and the skeleton's head indicates the outcome. Because of this structure, Ishikawa diagrams are sometimes referred to as fishbone diagrams. They are also referred to as Fishikawa, herringbone diagrams, or cause and effect diagrams.

An Ishikawa diagram places the central problem, known as the 'effect,' on the far right of the diagram. A line, known as the 'spine,' is drawn to the left, and other branches, which are types of causes known as 'affinities,' shoot off above and below it. Smaller branches can then be added to these affinities to add specific causes during brainstorming sessions.

Types of Ishikawa diagrams

The different types of Ishikawa diagrams include:

The 6Ms Ishikawa diagram

The 6M diagram organizes information into six categories: man, machine, material, method, mother nature, and measurement. It is most commonly used in the manufacturing industry. For instance, it could be used to identify bottlenecks slowing down the manufacturing process in a candle business.

The 8Ps Ishikawa diagram

The 8P diagram organizes information into eight categories: procedures, policies, place, product, people, processes, price, and promotion. It is most commonly used in the service industry. For instance, it could be used to improve the efficiency of a housekeeping business.

The 4S's Ishikawa diagram

The 4S diagram organizes information into four categories: suppliers, systems, surroundings, and skills. It is most commonly used in the service industry. For instance, a restaurant could use it to determine why the number of customers has declined over the past year.

Simple fishbone

A simple fishbone diagram has no predetermined causes or categories of causes. This is useful for organizations that want to create and set their own unique affinities. For instance, a software company will have very different affinities to a pet food manufacturer.

3Ms/Man machine material fishbone

The 3M diagram, also known as the 'man, machine, material' fishbone, organizes information into three categories: manpower, machinery, and materials. It is most commonly used in the manufacturing industry. For instance, it could be used in a food processing plant to determine why product quality has declined.

Ishikawa diagram

When to use an Ishikawa diagram

Ishikawa diagrams are a useful way to clearly visualize the potential causes of a specific event or problem. For instance, a team can use an Ishikawa diagram to identify bottlenecks or weaknesses within a business proposal and make the required adjustments.

Some popular use cases for Ishikawa diagrams include:

Product development

Ishikawa diagrams are often used in product development to outline the steps involved in the process clearly. This helps teams to determine which resources will be required at specific times and can also help to identify potential quality control issues.

Troubleshooting processes

Organizations often use Ishikawa diagrams to troubleshoot processes and resolve problems within a system. This is because the diagram makes it easy to consider all the possible causes of an issue within each category.

For instance, the 4S's diagram suggests that the possible causes could be related to suppliers, systems, surroundings, or skills.

Root cause analysis

Ishikawa diagrams are often used to identify the underlying cause of a failure in a product or process.

Problem-solving teams should first create a problem statement that includes information such as: what product failed, failure observations, the number of failed units, and the customer's description of the failure.

They should then create an Ishikawa diagram, which visually depicts the hypotheses that could explain this failure. The diagram elements should help explain what was responsible for the failure.

Benefits of Ishikawa diagrams

Some of the key benefits of Ishikawa diagrams include:

Helps identify potential causes of a problem

Showing all of the causes in the chain illustrates every possible reason that could lead to a problem simultaneously.

Even if the solution isn't immediately obvious, having a clear visualization makes it possible to eliminate some false positives quickly. This can stimulate team members to work out the potential causes of a problem more quickly.

Reveals areas of weakness or bottlenecks in current processes

Ishikawa diagrams make it easy to understand the correlation between relationships. This makes it obvious when certain stages of the process restrict the system's flow. As a result, any weakness or potential bottlenecks can quickly be identified and monitored before they cause issues.

Accelerates problem-solving

Given that Ishikawa diagrams provide an overview of all the potential causes of a certain result, it facilitates brainstorming, which can accelerate problem-solving. It also helps teams maintain their focus because it provides a clear pathway to analyze every involved pathway.

How to make an Ishikawa diagram

Here is how you can create an Ishikawa fishbone diagram in four easy steps.

  1. Identify and agree on the exact problem. The first step of creating an Ishikawa diagram involves identifying, agreeing, and writing down a problem statement. Determine the exact issue, who is involved, and when and where the problem occurs.
  2. Document the problem. Write the problem statement in a box on the right-hand side, and then draw a horizontal line from your problem statement. The fish's head represents the problem statement, and the horizontal line resembles the fish's spine.
  3. Brainstorm the major categories of causes. Brainstorm with your team to decide how to categorize the significant factors causing the problem. For instance, these could be systems, materials, equipment, people, or external forces. Draw a line off the spine of the fish diagram for each cause. Then, label each line at the top.
  4. Identify potential causes of the problem. Identify the potential causes of the problem that may be behind each factor. Draw shorter lines off the bones of the fish diagram to help you visualize these potential causes. You may need to draw smaller sub-branch lines off a cause line if that particular cause is a bit more complex.
  5. Analyze the diagram. At this stage, you should have a fully fleshed fishbone diagram that indicates all the possible causes of the problem statement. You can now research the issue further using investigations and surveys. Once you have narrowed down the possible causes, you should be able to find the culprit.

Why use MindManager to make Ishikawa diagrams

You can make Ishikawa diagrams by hand or in any graphic design program or use a program specifically designed for Ishikawa diagram making. MindManager, an industry-leading Ishikawa diagram software, allows you to create complex, detailed Ishikawa diagrams with ease.

MindManager's key benefits include:

  • User-friendly, intuitive interface
  • Extensive image library—over 700 topic images, icons, and symbols to add to your Ishikawa diagrams
  • Premade Ishikawa diagram templates
  • Convenient file storage, retrieval, and sharing
  • Powerful integrations with file storage apps like Box and OneDrive
  • Google Docs integration via Zapier
  • Various tools and features to facilitate brainstorming and strategic planning
  • Google Chrome extension—MindManager Snap—to easily collect and import text, links, and images from the web

MindManager helps you synthesize ideas and information by providing a simple, intuitive framework for organizing your thoughts. With MindManager, you and your team can clarify complexity and collaborate in new and unexpected ways.

Ishikawa diagram templates

MindManager comes pre-installed with many Ishikawa diagram templates. To use these templates:

  • Open MindManager
  • Click NEW in the navigation menu
  • Select the template you want to use
  • A preview screen will appear - check to see if you'd like to use your selected template
  • Select 'Create Map'
  • Customize the template for your specific project

Ishikawa diagram FAQs

What does an Ishikawa diagram show?

An Ishikawa diagram shows the potential causes of a specific event or process.

What is an Ishikawa diagram used for?

An Ishikawa diagram is typically used in manufacturing and product development to outline the sequence of steps in a process. This can help teams identify a problem's potential causes, reveal areas of weakness or bottlenecks in current processes, and accelerate problem-solving.

Using Ishikawa diagrams to identify the causes of a problem

Ishikawa diagrams are designed to show the potential causes of a specific event or process. They are typically used during product development, root cause analysis, and troubleshooting processes.

They can help your organization to identify the potential causes of a problem, reveal areas of weakness or bottlenecks in current processes, and ultimately accelerate problem-solving within teams.

Visualize more with MindManager

Want to visualize your processes and remove the bottlenecks within your organization? Give MindManager a try today and start building Ishikawa diagrams with our easy-to-use templates.

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