Cause and Effect Diagram (Ishikawa) Summary The development of the cause and effect Fishbone diagram is credited to Kaoru Ishikawa, who pioneered quality management processes in the Kawasaki shipyards. The cause and effect diagram is used to explore potential causes (or inputs) that result in a single undesirable effect (UDE, or output). Causes are categorized under six headings, namely Machinery, Methods, Measurement, Manpower, Materials, and Environment. Potential causes can be arranged according to their level of importance or detail, resulting in a depiction of relationships and hierarchy of events. It is the hierarchy that creates a map that looks somewhat like fish bones, hence the name. The Ishikawa Fishbone Diagram is intended help you brainstorm and search for potential root causes or identify areas where there may be problems by questioning the existence of causes under each of the six categories. Ishikawa Fishbone Template UDE Materials Manpower Machinery Methods Measurement Environment Causes, inputs, or sources of variation A UDE is an U n D esireable E ffect A visual brainstorming tool used to help identify and categorize potential root causes named for Kaoru Ishikawa.