
The Ishikawa Principle is a method for root cause analysis of problems, also known as the Ishikawa Fishbone Diagram, Ishikawa Diagram or Cause and Effect Diagram. It was developed by Japanese engineer and quality management expert Kaoru Ishikawa.
The Ishikawa principle is based on the idea that a problem often has many different causes and that these causes can be divided into categories. The diagram itself is in the shape of a fish skeleton, with the head of the fish representing the problem and the bones of the fish representing the different categories of causes.
Typical categories that can be used in the Ishikawa diagram are “method”, “material”, “machine”, “employee”, “measurement” and “environment”. The individual causes are then classified into the appropriate categories.
The Ishikawa diagram is a useful root cause analysis tool because it helps break down complex problems into smaller, easier to work with pieces. It also encourages thinking in context and supports the identification of causes that might have been overlooked had they been considered individually.
The Ishikawa principle can be used in various areas, such as quality management to identify the causes of production defects, or project management to analyze the causes of delays or problems in project implementation.