2. What is the Ishikawa cause-effect diagram method?

The method consists, first and foremost, of a graphic representation of the possible causes of a defect or failure. The effect is what has been directly observed (e.g. the part cannot be positioned in its intended location). The main problem may be the subject of a summary analysis "the part is too long", or it may be the subject of a complete analysis identifying all the ins and outs (for example, with the QQOQOCP method).

The scope of application of the Ishikawa diagram is extremely wide. It's a quick and easy tool for visualizing the possible causes of an observed effect and facilitating the search for ways to remedy them. It simplifies analysis work, and therefore facilitates and stimulates the search for solutions.

Five to nine categories are used to classify and group possible causes of the problem.

The diagram...