Fishbone diagram: Solving problems properly

Every company faces its own problems. Often managing directors and employees are forced to deal with new chal­lenges every day. But how wise is it having to overcome the same obstacles every day? Instead of dealing with the symptoms, the root of the problem must be addressed. But finding the cause of a problem is not an easy task. The fishbone diagram assists in iden­ti­fy­ing the cause of a problem.

The fishbone diagram, invented by Ishikawa Kaoru, a Japanese chemist, (hence why it is also referred to as the Ishikawa diagram) aims to help companies find solutions to problems and their causes in a struc­tured way. It is therefore also called the cause-effect diagram. Every problem, requiring a sus­tain­able solution, is graph­i­cal­ly il­lus­trat­ed with its re­spec­tive causes in the diagram.

The problem that needs to be addressed is on the right side of the diagram. It is written down before any other ob­ser­va­tions are made. Be as accurate as possible when de­scrib­ing the problem and write it on the right hand side of the flip chart or black­board. You then draw a line or an arrow to the left i.e. pointing towards the problem. Several other lines branch off from this main line: the possible causes of the problem. When spec­i­fy­ing the potential causes of the problem, you can use several methods: the 4M method, and its ex­ten­sions the 5M and 8M methods, are fre­quent­ly used. They refer to the main in­flu­enc­ing factors of processes, which often lead to problems.

The 4M method uses the following main in­flu­enc­ing factors:

• Material
• Machine
• Method
• Man

The 5M method also uses the ad­di­tion­al factor of:

• Mother Nature

When using the 8M method, three ad­di­tion­al factors are used:

• Man­age­ment
• Mea­sure­ment
• Money

The lines branching off from the main line list the actual causes of the problem and are arranged according to the ap­pro­pri­ate cat­e­gories. These causes should be iden­ti­fied very ex­plic­it­ly as opposed to the rather broadly defined main in­flu­enc­ing factors.

As an example of how this diagram can be applied in practice, imagine a company with in­suf­fi­cient customer support. This company receives repeated com­plaints that the hotline does not offer any help.

As a first step, the problem must be stated precisely: “In­suf­fi­cient support” is not a good enough statement for our example. The more detailed the problem is explained, the more effective the fishbone diagram can be. The problem is written to the right of the arrow.

Now the possible cat­e­gories of causes, which lead to this problem, must be defined. In our example we use all the terms of the 8M method.

• Material: Type of customer queries
• Machine: Technical equipment of the support team
• Method: Workflows of the support team
• Man: Staffing of the support team
• Mother Nature: Type of customer
• Man­age­ment: Support by the man­age­ment
• Mea­sure­ment: Key figures of the support team
• Money: Budget of the support team

These basic factors are now added to the fishbone diagram. Lines branch off from the main line to these terms.

Next to the category lines, the specific causes of the problem can be added. It is rec­om­mend­ed to complete the fishbone diagram as a team. In par­tic­u­lar, it should be done with those employees, who are directly involved in the problem-causing processes. The team should be mixed since if people with different expertise are involved, there’s more chance it will lead to ex­tra­or­di­nary ideas. Brain­storm­ing is required in order to find the causes. As a group all potential causes are to be iden­ti­fied.

For example, under “Material” it would be a good idea to comment on the type of customer inquiry. Also “Lack of knowledge on the customer’s part” as well as “Rudeness of the customer” could be added.

When analyzing the problem, further sub­cat­e­gories can be elab­o­rat­ed upon. With such a level of detail, the causes of the problem can then be de­ter­mined. For example, the rudeness of the customers could be explained by ex­ces­sive­ly long waiting times on the hotline.

In order to find the real cause of a problem, the 5W method is used. Here the “why” question is asked five times in order to get to the root of the problem.

A solution to the problem requires time. Rushing the process is counter-pro­duc­tive. If a cause is over­looked, the whole project might be in peril. If you try to find the causes of a problem too quickly, you’ll be in danger of dis­cov­er­ing only some of the causes but over­look­ing the most important ones.

In the best-case scenario, you’ll be able to see the causes of a specific problem emerging after creating a fishbone diagram. But it is not effective if you tackle all issues si­mul­ta­ne­ous­ly. If you spend your energy and resources in this manner, there is a risk of investing a lot of time and effort in solving a problem, without remedying any cause. It is important to con­cen­trate on only one cause of the problem - namely the most important one!

Pri­or­i­ties can also be set as a team. Each employee state their opinion as to what is the most serious cause of the problem. Con­tin­u­ing using the diagram, each person can evaluate the se­ri­ous­ness of the causes by giving points. The cause with the most points will then be the top priority. Before the vote, it is important to discuss the problem so that everybody has the same level of knowledge on it and does not rely on their gut feeling.

The last step is to tackle the problem by erad­i­cat­ing the cause or causes. However, it is first necessary to check whether the correct cause has been iden­ti­fied at all. This can be verified with a sig­nif­i­cance test, so that suitable methods can be iden­ti­fied to solve the problems.

The cause-effect diagram provides a creative approach to problem-solving within an or­ga­ni­za­tion. The graphic il­lus­tra­tion and the joint de­vel­op­ment of the diagram often lead to new insights, even when things seem to stall. But it is important to remember that the fishbone diagram sim­pli­fies things a lot. Often the com­plex­i­ty of business processes is ignored. Thus, neither temporal causal­i­ties nor mutual cor­re­la­tions may be rep­re­sent­ed.

In addition, there is a risk of creating chaos if the com­plex­i­ty of the problem is il­lus­trat­ed com­pre­hen­sive­ly in a diagram. The aim of the fishbone method is to create order in order to solve a problem. By clas­si­fy­ing into cat­e­gories and sub­cat­e­gories, the problem becomes more tangible and can be solved more sys­tem­at­i­cal­ly. Despite the cre­ativ­i­ty needed, the method also requires a dis­ci­plined approach to reduce the relevant issues in order to remain effective.

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