The essence of the Ishikawa diagram method and how to construct it

Hello, dear readers of Valery Kharlamov’s blog! The Ishikawa Method was invented by Kaoru Ishikawa, a professor at the University of Tokyo and the founder of the School of Management, as well as a quality specialist. Let’s look at what it is useful for and how to use it.

Features and Features

The Ishikawa diagram is also called the fishbone method and root cause analysis. It is presented in the form of a diagram, thanks to which it becomes possible to investigate and identify the factors of the negative consequences of an activity or process, as well as to anticipate and prevent their occurrence in the future. Most often it is used to develop new products, ideas or technologies, as well as to clarify the difficulties in the provision of services, the manufacture of products, equipment breakdowns, and so on.

The main advantages:

• It makes it possible to concentrate on the very content of the complexity that has arisen;
• Thanks to it, a discussion may arise in the team, during which weaknesses, pitfalls and other difficulties of the entire working system are identified. As a result of brainstorming about overcoming obstacles, there is a high probability of getting a creative and effective solution to the problem;
• Easy to understand and applicable in any situation;
• The effect of collective knowledge is created when all employees of different levels are included in the process and, depending on their position and competence, can make changes. For example, a manager may not have much information about the exact composition of the material of manufactured products, so they will focus more on the opinion of employees who are directly responsible for the storage conditions and quality of goods, the purchase of raw materials, etc.;
• The causes of troubles are formed into separate categories, which is very convenient for discussion. The people responsible for them can take turns in the process, giving the rest the opportunity to rest.

Algorithm of actions and recommendations

1. purpose

The first step is to agree on the problem statement or goal itself with all participants in the root cause analysis. Otherwise, the disagreements that have arisen in the process will make it impossible to obtain the desired result.

2. Registration

1. Choose a material that is convenient for you on which you will draw a «fish skeleton», it can be a regular sheet of paper, a board, and so on.
2. To improve the efficiency of perception, indicate the problem itself on the right side of the sheet, and draw a horizontal line to the left, from which you will draw diagonal small arrows that are responsible for the main problems that prevent you from achieving positive results. In this case, you really get a «backbone of a fish.» Most often they are divided into groups in order to structure and simplify the processing of information.

3. Template

I will give an example, a pattern that occurs most often. Let us take as a basis the complexity, which lies in the fact that the enterprise has produced products, or more precisely, several batches that turned out to be defective, defective. So, the categories for the schema:

• «People» — here the reasons for the human factor are indicated, for example, the appearance of a new inexperienced employee, the illness of a member of the team who subsequently made a mistake, low motivation, which causes negligence in one’s duties, possibly internal conflicts or difficult relationships with the leader, if they decided to take revenge on him in this way, disrupting the project.
• “Methods” — it may be time to make changes, as old methods or technologies no longer work, or fail, which is reflected in the quality of the product.
• «Mechanisms» — here it is already a matter of the equipment itself, with the help of which products are produced. It is necessary to inspect, possibly repair a breakdown or replace parts that have worn out. And sometimes the introduction of more modern equipment entails such consequences as low-quality, defective products.
• «Material» — in this cell you should indicate the characteristics of the material that is used in production. For example, composition, temperature, resistance, etc. It is possible that the batch of material is slightly different in property from the one normally used, which led to the defects.
• «Control» — taken into account the measures taken to prevent defective goods.
• «Environment» — for example, a change in weather conditions could affect the production process. For example, poor visibility, high or low temperature in the shop…

4. Filling

1. Now it is necessary to indicate the secondary factors that are related to the main ones, and they should be displayed in the figure as “medium bones”. Then they seem to adjoin the main diagonal ones.
2. Next, draw even smaller «arrow-bones» that are adjacent to the middle ones. These will be tertiary difficulties that affect the secondary ones. In the case when they are not there, you still draw arrows, they may “pop up” in the future, so you need free space in reserve.
3.  Indicate even the slightest and insignificant nuances, at the end of the analysis it may turn out that they actually play a major role. And a little tip: highlight with color those factors that, in your opinion, negatively and positively affect the result. For example, red color — threatening or destructive moments, green — help to develop. Then it will be easier for you to navigate in all schemes, blocks and branches.

5. Analysis

• All factors must be evaluated, ranked according to the significance of their impact on the problem.
• It should be taken into account that until the analysis of the diagram is completed, it is not worth moving on to specific actions, this may interfere with the expected results.
• Try every time you add factors that negatively affect the effectiveness of your process to the “bone” or “ridge” to ask yourself the question: “Why?”. Such reflection will help generate ideas and understand the sequence of events.
• Do not ignore data such as names, time, exact location and other points directly related to the problem you want to solve.

Example

To make it clearer, our example in the form of an Ishikawa diagram:

If you follow the algorithm, you will be able to “look” at the complexity that has arisen from a different angle, more voluminously, objectively, and also see the whole chain of events that influenced its occurrence. But this method also has disadvantages, which may well lead to analysis errors.

First, it is almost impossible to verify the diagram by building a logical chain of facts from the main cause to the consequences. That is, vice versa. And, secondly, the fragmentation of information, which in a large volume greatly complicates the perception of a holistic picture. Agree, it is difficult to focus when there are many branches (bones) and blocks.

Conclusion

And that’s all for today, dear readers! Try, experiment and apply this method of root cause analysis in your work, because it is not in vain that it has been popular for more than 50 years. I also recommend that you read the article: “The indispensable technology of the case method: stages and examples of use”.

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