Fish-bone Diagram

Dr. Kaoru Ishikawa, a Japanese quality control statistician, invented the fishbone diagram. Therefore, it may be referred to as the Ishikawa diagram. The fishbone diagram is 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 referred to 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. 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.

it can be used when the team...

- needs to study a problem/issue to determine the root cause

- wants to study all the possible reasons why a process is beginning to have difficulties, problems, or breakdowns

- needs to identify areas for data collection

- wants to study why a process is not performing properly or producing the desired results

The 4 W's of the Fishbone diagram should be considered. The 4 W's are:

1. What - refers to questions concerning objects such as machines and materials,
2. Why - which is concerned with questions on the conditions such as motivation,
3. When - refers to problems concerning the time sequence in the process such as the time of day or sequence in production,
4. Where - is concerned with the effects associated with place, such as a production line, branch office, or loading dock.

For manufacturing problems, the 5 M's are a useful tool in finding possible causes to a problem.

Ü The 5 M's are characterized as

- manpower,

- materials,

- methods,

- machines, and

- measurements.

For problems that are being examined in the service industry, the 5 P's can be used to develop the Cause Effect (CE)/Fishbone diagram:

- People (employees)

- Provisions (Materials & Machines)

- Procedures (processes/ Methods)

- Place (environment)

- Patrons (customers)