When to use the 5 Why method?

The 5 Why method is one of the methods to detect the causes of problems. Asking several “Why?” questions allows you to get to the source of the disturbance, thoroughly investigate its cause and focus on solving it effectively. By asking “Why?” questions, the problem becomes clearer, making the root cause easier to identify and eliminate.

The 5 Why method allows you to answer the questions:

• Why did the problem arise?
• Why did we not notice it?
• How to solve it?

In summary, this tool allows us to find out the cause of the problem and why it was not detected earlier.

How to perform a good analysis of a problem using the 5 Why?

Gather as much information about the problem as possible.

Gathering as much information as possible about the problem that has arisen affects the quality of the subsequent analysis and increases the likelihood of finding the actual root cause of the problem. At this stage, ask questions such as:

• When did the problem arise?
• What actually happened?
• What is the scale of the problem?
• What threat does it create?

Create a team and assign a leader.

Creating an interdisciplinary team with a good leader is essential. Make sure that the team includes representatives of different departments, people with expertise in different areas. Looking at the problem by such a team allows to objectively assess the situation and find the cause of the problem faster.

Set the rules and provide the tools.

When starting the analysis, set the rules and present them to the team. For example, ask them to turn off or mute their cell phones. Ensure good atmosphere and high work culture.

Properly describe the problem.

If you already have information about the problem – describe it accurately. The correct formulation of the problem is very important. Everyone who is involved in the analysis must understand what has happened and what the problem actually is.

Ask the “Why” question.

The team leader’s job will be to ask questions. The leader will ask an unspecified number of questions that bring the entire team closer to finding the cause of the problem. Remember that answers to questions must be based on facts or data. Being driven by emotions and subjective opinions can create chaos.

Solve the problem and take action.

If the cause of the problem has been found, the next step for you is to implement corrective action. To do this, you should create a corrective action plan. Remember to monitor this plan, check the implementation of each task, and see if it has produced the desired results.

Useful tools

Use a whiteboard or a pre-designed form, printed on a large sheet of paper, to conduct the analysis. It is important to visualize the path to the root cause of the problem. Then the problem will be better understood by the whole team.

Valuable tips

When conducting an analysis of the 5 Why’s:

• Ensure the logic of the cause and effect sequence.
• Distinguish between causes and symptoms of a problem.
• Don’t jump immediately to a potential solution of the problem – avoid shortcuts.
• Remember that the system is responsible for 85% of causes and 15% are human error issues.
• Remember that eliminating the root cause is to ensure that the same problem does not occur again.

Example of the 5 Why method use

PROBLEM: Blown fuse in a device

Why did the fuse burn out?
– Motor overloaded
Why was the motor overloaded?
– Insufficient oil flow through the pump.
Why is there not enough flow?
– Because the filter was blocked.
Why was the filter blocked?
– There was swarf in the oil.
Why was there swarf in the oil?

Root cause of the problem: There was no oil filler cap.

Advantages and disadvantages of the 5 Why method

Among the advantages of this method we can include:

• No need to prepare the team of employees in advance.
• Inducing employees to think analytically.
• Universality. This method can be used in any organization.
• Involving employees to actively participate in improving the organization.

Among disadvantages, on the other hand, we can include:

• Probability of drawing wrong conclusions as a result of reaching the cause by deduction.
• Lack of effectiveness when there are many real causes of the problem.