Fish diagram

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Kaoru Ishikawa, Professor of Tokyo University, he published the assumptions of his chart in 1962. The purpose of this method is to identify causes of incurred or potential failures. For this reason, it is also known as a cause and effect chart, and due to the distinctive look - fish chart. The scope of application of this method was initially limited to industry, but in a short time, it has proven to be useful in many other areas. It can by successfully used in services, public administration, project management.

The preparation of the chart must be effort of many employees in the organization, because the causes of failures usually have their sources in various fields of operation. That's why the team should consist of people with high expertise, who, in addition, have a willingness to disclose the causes of defects, also those caused by themselves. Heuristic methods prove to be useful when creating Ishikawa chart.


Chart consists of the arrows along with descriptions, merging in such a way that the main arrow indicates the final effect, which is usually a description of the failure.

Categories of causes usually are selected from a set of:

in accordance with the principle of 5M + E. It is also possible to use other categories (e.g. procedures, equipment, information, people) depending on the area in which the chart is used. Each category is developed through indication of causes. If necessary, also secondary causes can be shown. Expansion of the chart ends at the moment the full identification of the causes of the phenomenon.