What is the Fishbone Diagram?

Some of you might have heard about the Fishbone Diagram for effective problem-solving. So, what is the Fishbone Diagram? The Fishbone or Ishikawa diagrams were created in 1968 by Kaoru Ishikawa who was a Japanese Professor at the University of Tokyo and was famous for his inventions for quality management.


It is a pictorial representation and categorization of possible known causes to a problem, usually gathered during brainstorming. Since the shape of the diagram resembles a fish skeleton,  it is popularly known as the Fishbone Diagram. This diagram is being used across several software and manufacturing organizations as a simple visualization tool to depict various potential causes to a problem. It provides a structured way to organize and represent data in a meaningful manner.  


This technique can be used whenever there are many possible causes to a problem or whenever there is a need to identify causes to a complex problem. One can apply the fishbone diagram method in solving day-to-day problems as well. Though this is mostly a group technique, this technique can also be used by an individual as a tool to structure thoughts and identify root causes.


Categories of a Fishbone Diagram

The most commonly used categories for identifying the potential causes to a problem are listed as below:

  • People
  • Methods
  • Materials
  • Machines
  • Measurements
  • Environment


The 'People' category helps us to identify all causes that are people related. Here's an example. One of the leading software organization was having major quality issues and one of the primary causes was the unavailability of skilled resources. When represented on a fishbone diagram, this cause, Unavailability of skilled resources, will appear under the ‘People’ category.


Any causes that deal with the process or method to perform an activity are listed under ‘Methods’ category. Primary causes such as Inefficient development processes, Unnecessary effort spent by the team, etc. are few examples of the causes that fit well under the ‘Methods’ category.


The ‘Materials’ category is specific to any material or parts required to produce a product. This category is more common in the manufacturing industry. However, within software organizations, this category can be used to group any causes related to external dependencies. For example, if you are making changes to a front-end application that calls a service to fetch some values and if you hit a roadblock, then a primary cause such as Unavailability of the dependent service will be represented under this category.


The ‘Machines’ category is used to group all the causes related to hardware, software, and tools. For example, one of the primary causes of poor system performance could be the Unavailability of additional servers. Then again, one of the primary causes of ineffective communication within an organization could be the Unavailability of collaboration tools. Such causes are usually grouped under the ‘Machines’ category on a fishbone diagram.


The ‘Measurements’ category is used to group the causes that relate to incorrect data to measure the quality or success of the product. Consider an example where your team has launched a new website but the product goal to reduce call volume to the service center is still not met. Now, if one of the primary causes to this problem is the Incorrect data gathered during user research of the product, then this primary cause will be represented under the ‘Measurements’ category on a fishbone diagram.


Causes that relate to an environment are usually grouped under the ‘Environments’ category. For the manufacturing industry, an example of an environment-related cause is Lack of appropriate weather conditions or location. For software organizations, an example of such a cause could be Instability of development, test or production environments.


Though the above categories are the most commonly used categories for a fishbone analysis, people often tend to brainstorm the categories that are relevant to the problem they are trying to solve.


Now that you better understand the Fishbone Diagram, learn the steps needed to conduct a Fishbone Diagramming session with your group. Also read about other problem-solving techniques such as Brainstorming, Failure Modes and Effects Analysis (FMEA), SWOT Analysis, 5Whys, etc. with my book, An Expert Guide to Problem Solving - With Practical Examples.


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