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Cause and effect diagram

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  • 1. Cause and Effect Diagram Reporter: Almanon, Chelsea E. Blen, Rose Angelique M.
  • 2. Cause and Effect Diagram The Cause & Effect (CE) diagram, also sometimes called the fishbone diagram or Ishikawa diagram
  • 3. Inventor The CE Diagram was invented by Professor Kaoru Ishikawa of Tokyo University, a highly regarded Japanese expert in quality management. He first used it in 1943 to help explain to a group of engineers at Kawasaki Steel Works how a complex set of factors could be related to help understand a problem.
  • 4. Inventor Dr. Kaoru Ishikawa, a Japanese quality control expert, is credited with inventing the fishbone diagram to help employees avoid solutions that merely address the symptoms of a much larger problem. CE Diagrams are also often called Ishikawa Diagrams, after their inventor, or Fishbone Diagrams because the diagram itself can look like the skeleton of a fish.
  • 5. Purpose The major purpose of the CE Diagram is to act as a first step in problem solving by generating a comprehensive list of possible causes. It can lead to immediate identification of major causes and point to the potential remedial actions or, failing this, it may indicate the best potential areas for further exploration and analysis. At a minimum, preparing a CE Diagram will lead to greater understanding of the problem.
  • 6. Purpose A fishbone diagram is useful in brainstorming sessions to focus conversation.
  • 7. How to draw CE Diagram Step 1 Write down the effect to be investigated and draw the 'backbone' arrow to it. In the example shown below the effect is 'Incorrect deliveries'.
  • 8. Step 2 Identify all the broad areas of enquiry in which the causes of the effect being investigated may lie. For incorrect deliveries the diagram may then become:
  • 9. Step 3 This step requires the greatest amount of work and imagination because it requires you (or you and your team) to write in all the detailed possible causes in each of the broad areas of enquiry. Each cause identified should be fully explored for further more specific causes which, in turn, contribute to them.
  • 10. Different types of CE Diagram 1. Production classification type This type differs from the basic type above in that each discrete stage in the production process leading up to the effect being examined is shown along the main arrow or 'backbone' of the diagram. Possible causes are then shown as branches off these as shown in the illustration overleaf.
  • 11. Different types of CE Diagram 2. Cause enumeration type This is not so much a different type of diagram but a different method of constructing a diagram. Instead of building up a chart gradually (starting with the 'backbone', deciding broad areas, then adding more and more branches), you postpone drawing the chart and simply list all the possible causes first. Then draw the chart in order to relate the causes to each other.
  • 12. Different types of CE Diagram 2. Cause enumeration type This method has the advantage that the list of possible causes will be more comprehensive because the process has a more free-form nature. The disadvantage is that it is more difficult to draw the diagram from this list rather than from scratch.