Tiffany and Shane examined the problem from another aspect and worked together on the Cause and Effect diagram. It was now their time to provide insight into this Tool.
What exactly is an Ishikawa Diagram?
A cause and effect diagram is a visual tool used by management to identify the causes of problems (effects) that vary in nature. Dr. Kaoru Ishikawa, a Japanese quality control expert, is credited with inventing the fishbone diagram. When used within the manufacturing context, 6M’s are used – Material, Method, Man (manpower), Machine, Measurement and Mother Nature (environment). It is important to note that the first 4M’s form the basis of the diagram while the final 2 M’s are added when necessary or relevant.
This link may also be helpful in your understanding: Click Here
Why/when is a cause and effect diagram used?
Cause and effect diagrams are used because they effectively put ideas that surface during the process of brainstorming into perspective (categories). It helps employees avoid solutions that merely address the symptoms of a much larger problem. This diagram can be used when you are identifying possible causes for a problem, especially when the problem has many causes and you need to place priority on the various causes.
How to construct a cause and effect diagram?
After a problem/effect is identified and or felt, it usually sparks concern. Those affected begin to question and or wonder about the possible cause(s).
The problem is written in a box to the centre right side of the page. A straight line is then drawn from the centre of the box across the page to the left side with an arrow. Three (3) diagonal lines are placed on either sides of the centre line. Each diagonal line is labelled with the broad heading identified in the definition. The various causes identified will then be listed on subsidiary lines, extending out from each diagonal line under their respective headings. Be sure to place an arrow pointing toward the respective diagonal line on the end closest to the diagonal line with the relevant heading. At the end of it all, your diagram should resemble that of a “fishbone”!
The links below give you a visual and aural example:
How to interpret a cause and effect diagram?
In order to analyse this diagram, you would need to study the layout of your chart. First look for causes that appear repeatedly; generally these causes represent root causes. Root causes would have the largest effect on the problem so you should aim to address these problems first. If you notice a thick cluster of items in one area, this may indicate a need for further research into these particular causes. If several major branches have only a few sub-branches, you may need to combine them under a single category, since these may have little or no effect on the problem at hand. Lastly, you would need to assign weights to the major causes to help determine the complexity and importance of each of them in order to solve your problem.
Evaluation:
The manufacturer of Tropical Paradise has been receiving complaints that the sweet crumbles too easily. When purchased and opened they are already broken up or cracked and on the verge of crumbling. To aid in solving this problem a team brainstormed some possible causes which include: lack of training, poor quality inputs, temperature, brix level too low, insufficient cooling time, wear and tear, poor measuring method, poor measuring skills, Ph level, lack of consistency, faulty equipment, different brands, humidity, boiling technique, brix level too high.
Using the 6M’s used in the manufacturing industry, list the above causes under their respective headings on the fishbone template provided here. Just “right click” on the various boxes and select “add text” then type in your response. The entire diagram is worth 14 marks.
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