The Ishikawa diagram is shaped like a fish skeleton because its creator, Kaoru Ishikawa, was a quality control statistician in Japan who wanted to symbolize the idea that the diagram branches out in multiple directions, like the bones in a fish skeleton, to represent the many factors that can contribute to a particular problem. The shape also helped Ishikawa communicate the idea that the problem can be dissected to reveal its underlying causes.
Assuming the main problem in the fish head is "Late Deliveries", below are examples of problem statements that would go into the sub branches on the diagram:
|Main Issue||Sub Branch Problems|
|Supply Chain Delays||Late raw material procurement, Delayed transportation of materials, Quality control issues, Shipping delays|
|Production Issues||Machine breakdowns, Labor shortage, Inefficient processes, High rejection rates|
|Planning & Coordination||Inaccurate demand forecasting, Poor communication between departments, Lack of clear project timeline, Unclear roles and responsibilities|
|External Factors||Natural disasters, Port closures, Customs delays, Market fluctuations|
The team would plot each of the sub-branches identified in the table on the fishbone diagram as a branch off the main problem of "Late Deliveries." These sub-branches represent the potential causes of late deliveries, and the team would use these to brainstorm and analyze the root cause of the problem.
For example, under the sub-branch of "Supply Chain Delays," the team would plot each of the identified causes such as "Late raw material procurement," "Delayed transportation of materials," etc. The same would be done for each of the other sub-branches. This would provide a visual representation of the potential causes of late deliveries, and help the team to analyze the root cause and develop solutions to resolve the issue.