What is a cause and effect diagram? Root cause and application process

Cause and effect diagram is an important management tool that helps solve challenges that businesses are facing. So has the business applied it correctly? In this article, 1C Vietnam will present the concept of cause-and-effect diagrams and introduce the detailed construction process.

1. What is a cause and effect diagram?

The cause-and-effect diagram, also known as the fishbone diagram, was created by Japanese scientist Kaoru Ishikawa during his time working at Kawasaki Heavy Industries. This diagram has a simple design, similar in shape to a fish skeleton.

A cause-and-effect diagram is a form of organizational logic diagram that helps identify the root cause of a problem or represents the relationship between agents classified into 6 main groups: machinery, materials, human resources. , nature, measurement and methods.

The purpose of a cause-and-effect diagram is to make it easier to find and identify the causes of problems in product, service, or process quality. In particular, charts support interaction and multi-dimensional thinking to help solve problems effectively.

The meaning of a cause-and-effect diagram is to help discover the root cause of the problem and implement effective corrective and preventive measures. Clarity about the cause helps businesses focus on improving work processes and quickly responding to customer requests. To date, cause-and-effect diagrams are widely used in many fields.

2. Root cause in cause and effect diagram

In a cause and effect diagram, the problem is placed on the right side, or the fish's head, and the causes of the problem are placed on the left branches. These causes belong to 6 main groups:

• Mechanical Cause: The problem stems from mechanical failure due to improper or incomplete maintenance.
• Material cause: The process has problems because the materials do not meet standards, do not meet technical specifications, or because the volume is incorrect.
• Human resources causes: Problems arise due to staff incompetence, rushing to work, skipping process steps, or lacking dedication.
• Natural causes: Problems caused by peripheral environmental factors such as temperature, humidity, pollution, unstable weather, or inconvenient layout.
• Measurement cause: Inaccurate measurement data and standards, leading to potential problems in the production process.
• Methodological causes: Ineffective working methods, possibly due to lack of training for employees, or excessive reliance on machinery.

3. When to use cause and effect diagrams in business?

Fishbone diagrams, or cause-and-effect diagrams, are often applied in the early stages of workflow improvement. Here are the appropriate cases to use fishbone diagrams:

• When determining the cause of the problem
• Identify all root causes
• When many different opinions appear in an organization/group
• In Six Sigma projects

4. Ishikawa cause-and-effect diagram construction process

The process of building an Ishikawa cause-and-effect diagram is an important step in researching and analyzing the root causes of problems. Below are 4 steps to build a detailed cause-and-effect diagram:

Step 1: Identify the business problem that needs to be solved

In this step, businesses need to identify the specific problem that needs to be solved, located in the "fish head" part of the cause-and-effect diagram. Using the "5W" principle is an effective way to answer basic questions such as What (what is the problem), When (when does it happen), Where (where does it happen), Why (why does it happen? out), Who (who is involved) and How (how it happened).

Step 2: Identify the main causes affecting the business

Try to identify all the factors that influence the results including materials, machines, people, methods, environment, and measurements. If employees are working as a team to solve a problem, this is the right time to apply creative thinking techniques. Administrators need to systematically arrange groups of underlying causes so that they can easily analyze and find effective solutions.

A common method is to write the problem on the right side of the paper and draw a horizontal line dividing it in half, creating the "fish head" and "spine" portion of the diagram.

Step 3: Analyze the elements in the fishbone diagram

After determining the main cause affecting the business, in the next step the business will collect full problem information including the correlation of the problem between people, materials, environment, machinery, methods and measurements to analyze each factor one by one.

Below are examples of questions to ask for each major cause:

- Material

• Has the process of purchasing raw materials from suppliers been validated?
• Have the materials undergone proper inspection and handling?
• Is the quality of raw materials guaranteed?

- Human

• Does the employee/worker have enough experience and capacity to perform the task?
• Have employees/workers been trained to participate in the production process?
• Is there work overload for employees/workers?

- Environment

• Is the production process affected by changes in temperature, noise, light, etc.?
• Does the working environment ensure labor safety?
• Is workers' health affected by environmental factors?

- Machines

• Is the programming and operation of the machinery correct?
• Is there regular inspection and maintenance of machinery?
• Is operating machinery harmful to the environment and workers?
• Have machines used up their limited capacity?

- Method

• Are employees/workers trained to implement correct production methods?
• Have the new methods been tested?
• Do staff/workers have enough equipment to fully perform the process?
• Are operating methods changed and updated regularly?

- Measure

• Is measurement accuracy affected by the environment?
• Do the assessments fully cover the necessary standards?
• Does the machine measure data accurately?

Step 4: Provide corrective measures

Finally, for each cause, constantly ask "Why did this happen?" and record all the information collected in both the main branch and sub-branches. From there, determine corrective measures based on the information filled in on the diagram, focusing on addressing the specific cause and ensuring an effective and thorough solution.

Above is all the information about cause-and-effect diagrams, a powerful tool that helps businesses identify the root cause of the problem and the relationship of four factors. Hopefully, through the process of building a cause-and-effect diagram, businesses can quickly identify the main cause of the problem, thereby providing effective solutions and improving work processes.