Dr. Kaoru Ishikawa, a Japanese quality control statistician, invented the fishbone diagram. Therefore, it may be referred to as the Ishikawa diagram. The fishbone diagramis an analysis tool that provides a systematic way of looking at effects and the causes that create or contribute to those effects. Because of the function of the fishbone diagram, it may be referredto as a cause-and-effect diagram. The design of the diagram looks much like the skeleton of a fish. Therefore, it is often referred to as the fishbone diagram.
Whatever name you choose, rememberthat the value of the fishbone diagram is to assist teams in categorizing the many potential causes of problems or issues in an orderly way and in identifying root causes.
When should a fishbonediagram be used?
Does the team...
• Need to study a problem/issue to determine the root cause?
• Want to study all the possible reasons why a process is beginning to have difficulties,problems, or breakdowns?
• Need to identify areas for data collection?
• Want to study why a process is not performing properly or producing the desired results?
How is a fishbone diagramconstructed?
1. Draw the fishbone diagram....
2. List the problem/issue to be studied in the "head of the fish".
3. Label each ""bone" of the "fish". The major categoriestypically utilized are:
▪ The 4 M’s:
• Methods, Machines, Materials, Manpower
▪ The 4 P’s:
• Place, Procedure, People, Policies
▪ The 4 S’s:
• Surroundings,Suppliers, Systems, Skills
Note: You may use one of the four categories suggested, combine them in any fashion or make up your own. The categories are to help you organize your ideas.
4. Use anidea-generating technique (e.g., brainstorming) to identify the factors within each category that may be affecting the problem/issue and/or effect being studied. The team should ask... "What are the...