Fishbone Diagram History, structure and solved example

 Fishbone Diagram

In real-world and business environment, problem-solving methodologies are crucial to minimize wastes and defects; thus, minimizing cost, lead time and maximizing cost. In order to solve the problem radically, we need to drill deep till we reach the root cause of the problem. From the most prominent methods to solve problems and get the root cause is the Fishbone diagram or Ishikawa diagram or cause and effect diagram. In this article, fishbone will be discussed in detail with solved example.

History of Fishbone Diagram

The Fishbone diagram was invented, in 1960, by Dr. Kaoru Ishikawa, from Japan to help the employees to bypass solutions that solve problems temporarily and not radically in shipyards industry. Nowadays, Fishbone diagram is used in most of industries all over the globe; additionally, it is one of the seven tools of quality management.

When to Use Fishbone Diagram?

The Fishbone can be used to:

-         Identify the causes of a certain problem.

-         Develop a new product avoiding issues in the existing market.

-         Find weakness points in business process.

-         Avoid repetition of a certain problem.

-         To measure the effectiveness of corrective actions.

How to Create Fishbone Diagram?

-         Define the desirable and undesirables causes that may affect the process.

-         Identify the main categories for causes using 6M (discusses below).

-         Brainstorming process with the responsible team.

Fishbone Diagram Structure

According to the below figure, the Fishbone diagram resemble to a Fish, where at the head the effect is written and the main categories are written in small boxes with arrows going to the body of the fish. The proposed causes are then written on the arrows going out from the boxes.

The 6Ms Approaches

The 6Ms are used to divide the fishbone diagram into categories. It is a well-known approach. All of them can be used or some of them. The 6Ms are:

-         Man.

-         Material.

-         Machine.

-         Measurement.

-         Method.

-         Media (Environment)

Fishbone Diagram Example

In order to clarify this problem, we will present an example to better understand the method. Consider a well-known cafe where the customers complain of bad taste of the coffee. The team made a reunion to discuss the potential causes for bad taste.

The brainstorming team has identified potential causes behind the bad taste of coffee. Concerning material, the beans are not freshly roasted and the used water comes from the tap; thus this could leads to bad taste of coffee. Concerning machine, it takes long roasting period and the coffee maker is not cleaned regularly causing bad taste.

After identifying the possible reasons, Corrective actions must be taken to avoid the repetition of the problem.