Cause And Effect Diagram

Purpose of Usage

It is an analysis tool that provides a systematic way of looking at effects and causes that create or contribute to those effects. It helps to assist teams in categorizing the many potential causes of problem or issues in an orderly way and in identifying root causes. Moreover, it can help to structure the quality improvement process, the diagram also depict the cause according to their importance. By mastering organization skills like working together as a team, and being open to different ideas, the diagram is a very attractive tool that is easy to learn and apply.

Historical Background

Kauro Ishikawa of Tokyo University in 1943 developed the Ishikawa Diagrams. The cause and effect diagram is also commonly known as the fishbone diagram due to its intricate appearance that resembles a fish bone. It is an important tool in helping people to identify the reasons why a process goes out of control. Dr.W.Edward Deming eventually adopted this tool in improving quality after the World War II and in his teaching of Total Quality Management since then. Both Ishikawa and Dr. Deming utilize this diagram as one of the first tools in the quality management process. The Cause & Effect (CE) diagram, also sometimes called the ‘fishbone’ diagram, is a tool for discovering all the possible causes for a particular effect. The effect being examined is normally some troublesome aspect of product or service quality, such as 'a machined part not to specification', 'delivery times varying too widely', 'excessive number of bugs in software under development', and so on, but the effect may also relate to internal processes such as 'high rate of team failures'.

How to successfully build a cause and effect diagram?

• Be sure everyone agrees on the effect or problem statement before starting
• Be succinct
• For each node, think of what could be its causes, add them to the tree
•  Pursue each lines of casualty back to its cause
• Consider grafting relatively empty branches onto others
• Consider splitting up overcrowded branches
• Consider which root causes are most likely to merit further investigation

Major categories in Cause and Effect Diagram

Causes in a cause and effect diagram are frequently arranged into four major categories.

• Manpower, methods, materials and machinery (Manufacturing)
• Equipment, polices, procedures and people (Administration or service)

A Typical Cause and Effect Diagram

Useful Software

Cause and effects diagrams are either drafted manually by hand on a sheet of paper, or constructed by utilizing computer software packages. Autocad, CDKEY and a variety of software can be subscripted via the Internet and be used for creating professional looking drawings and illustrations respectively. Creating the diagram is easy and also highly interactive for software user.

Recommended links

• Quality Improvement Tools
• Statistic Process Control
• Faq about Quality tools
• Ishikawa Diagram

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