Ahmet Can OLDAÇ- 030060098-week9 pt.2

Fishbone Diagram(old)

Fisbone diagrams or cause-and-effect diagrams were developed by Kauro Ishikawa of Tokyo University in 1943 and thus are often called Ishikawa Diagrams. They are also known as fishbone diagrams because of their appearence (in the plotted form). Cause-and-effect diagrams are used to systematically list the different causes that can be attributed to a problem (or an effect). A cause-and-effect diagram can aid in identifying the reasons why a process goes out of control. As such, they should be part of the plan stage of the PDCA Circle.

(Kumar, S., Total Quality Managment, p. 102)

Fishbone Diagram(new) [Management Planing] 

It is not possible to mention the topic of cause and effect without dealing with fishbone diagrams {also known as cause-and-effect diagrams, or Ishikawa diagrams). This is a visual aid to some forms of think­ing created and made popular by a renowned management guru by the name of Ishikawa (who is also attributed with the original thinking that eventually produced the 'five Ms and an E' concept). A typical base format for a fishbone diagram is shown in Figure 5.2.

The effect, or desired result, is placed as statement at one end of a line, representing the main back­bone, then categories of activities, conditions or occurrences that arc likely to contribute to it are drawn as main bones radiating from the backbone. More detailed items are then drawn from the main bones, and so on.

TIP

When creating a fishbone diagram, you may become stuck as to how to set the definitions for the main bones. You could start with 'five Ms

and an E\

The diagram is most commonly used as a problem-solving tool. It can work as a convenient way of organizing a group's thoughts when determining what might be the root cause of something that is going wrong. It can also, though, be used in a similar manner to plan for and understand cause-and-effect relationships.

Let us think about, for example, an output requirement relating to the lightness of our sponge cake. The main 'bones' that affect this could be recipe, preparation atid baking. From baking we could have subsidiary bones which are oven type, oven temperature, duration, position in oven and general conditions. Then we could create further subsidiaries from oven type - fuel type, fan-assisted.

domestic/industrial. It is then possible to break fuel down even further to show wood, oil. gas, electricity, quantity, purity and consistency. This gives us the more detailed diagram shown in Figure 5.3. For a real exercise we would also have to go as far as we could with each and every bone and its branches.

TIP

I have not completed the diagram here because it would look too cluttered on the page. When you are doing it for yourself, you may like to take a flipchart sheet or other large page size to make sure that you can lay it out without making it too intricate or unreadable.

This does not tell us exactly what the answer is to every problem, or exacdy what contributes most significantly to any effect, but it does help us to put down all our thoughts in a logical way and can prompt us <u think of things through its'drill-down' approach that we might otherwise miss.

One company for whom I present training courses advocates that its process teams should always use fishbone diagrams (o generate (he subsidiary measurements which relate directly to output controls. I would not go so far as to suggest that i( is always an appropriate device to use. but it can be helpful in many cases.

(The Organizational Measurement Manual, 2001, David Wealleans, P57)

-new definiton is better since it explains more