Anatomy of the Fishbone Diagram

What is a fishbone diagram? A fishbone diagram, also known as a cause-and-effect diagram, is a visual tool used to systematically list the different causes that can be attributed to a problem (or an effect). This tool is most useful in identifying the reasons why a process goes out of control. Its' creator, Dr. Kaoru Ishikawa of Tokyo University, developed this technique in 1943 to address process inefficiencies found within the Kawasaki shipyards of Japan.
Causes within a cause and effect diagram are typically made up major categories. The categories themselves may be anything that is appropriate to the problem that is being analyzed, however, you will often see:
• Manpower, methods, materials, and machinery (in a manufacturing environment)
o These are known as the 4 M's
• Place, policies, procedures, and people (in an administration or services environment)
o These are known as the 4 P's
• Surroundings, Suppliers, Systems, Skills (all environments)
o ...