If there is a problem in your processes it is important to know the correct root cause. There is no use to solve the wrong problem. To assist with this task there are many tools. One commonly used is the Ishikawa Diagram with a 4M or 5M layout. This added to the terminology section.

Ishikawa Diagram:

Also known as fishbone diagrams or cause-and-effect diagram. It is used to map possible causes and narrow them to find the root-cause or the cause of a specific phenomena.

4M:

A systematic approach to root cause analysis. Machine, Man, Method and Material. Often used as an Ishikawa Diagram.

5M:

An expanded version of 4M analysis where a fifth M is added, Measurements. Making it Machine, Man, Method, Material and Measurements. It is a systematic approach to root cause analysis often used as an Ishikawa Diagram.