6. Ishikawa method (cause-consequence-5M trees)

6.1 Origins and applications

Japanese professor Koaru Ishikawa began his engineering career in shipbuilding, and is the founding father of quality circles. In 1982, he finalized the Ishikawa diagram, also known as the fishbone diagram, cause-consequence diagram or cause-effect diagram, an extremely rigorous tool for identifying the various causes of a single effect, consequence or desired result.

The Ishikawa diagram provides the root causes of a problem, with a structured representation of...