What is 5Whys Analysis

Guide: 5 Whys

A problem-solving technique that involves asking "Why?" five times consecutively to drill down to the root cause of a problem. By repeatedly asking the question, the cause-and-effect relationship of the issue is explored.
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Daniel Croft

Daniel Croft is an experienced continuous improvement manager with a Lean Six Sigma Black Belt and a Bachelor's degree in Business Management. With more than ten years of experience applying his skills across various industries, Daniel specializes in optimizing processes and improving efficiency. His approach combines practical experience with a deep understanding of business fundamentals to drive meaningful change.

5 Whys is a problem-solving technique used to get to the root cause of problems by asking the question of Why multiple times, but often 5 times giving it the name “5 Whys”. This allows people to address the root cause of issues instead of the symptoms of the root causes which is often what is seen as the problem. 

Like a doctor diagnosing an issue such as neck pain, a painkiller will only address the symptoms of the neck pain and not the root cause of the pain. By getting to the root cause you can ensure a long-term fix to the root cause of the neck pain which could be caused by seating positions and not taking painkillers which is a short-term fix.

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What is the 5 Whys?

The 5 Whys is a root cause analysis problem-solving technique that aims to identify the root cause of a problem by repeatedly asking the question “Why?” five times or until the core issue is unveiled. Developed within the Toyota Production System, it’s one of fundamental tools in the Lean Six Sigma methodology.

Here’s how it works:

  1. Begin with a clear and concise problem statement.
  2. Ask “Why?” the problem occurred. Document the answer.
  3. If this answer doesn’t identify the root cause, ask “Why?” again and document the subsequent answer.
  4. Continue this process until you’ve either asked “Why?” five times or the root cause has been identified.

5 Whys Root Cause

Lets go through an example, let’s say a machine stopped working:

  1. Why? – The machine’s fuse blew.
  2. Why? – The machine was overloaded.
  3. Why? – There wasn’t adequate training on machine capacity.
  4. Why? – Training materials were outdated.
  5. Why? – There’s no review process for updating training materials.

In this case, the root cause is the lack of a review process for training materials, and addressing this will prevent similar issues in the future. Only treating the symptom in this situation would have been to change the fuse, for it then to regularly blow and cause additional downtime.

This is a good example where a machine stopping working’s root cause is cause by an issue what would not be obvious is first glace at the symptom of the problem and provides a clear example that root cause analysis is important to ensure that solutions are not jumped to before a through root cause analysis is conducted. 

Why is the 5 Whys Important?

Understanding the 5 Whys is important because identifying symptoms of a problem is not the same as uncovering its root cause. If you only address symptoms this provides only temporary solution to the problem. However, understanding and resolving the root cause can prevent the issue from reoccurring.

The 5 Whys Problem-Solving technique is also useful for:

  • Problem Prevention: By identifying the root cause of the problem, businesses can implement long-term solutions, leading to more robust systems and processes and prevent the problem reoccurring.

  • Cost-Efficiency: Addressing root causes is often more cost-effective in the long run as it prevents recurrence and the associated costs of repeated problem-solving which usually involves the same people constantly firefighting the same issues such as repeated machine breakdowns.

  • Improved Processes: Regular use of the 5 Whys to identify the root causes of problems can highlight weaknesses in processes, leading to continuous improvement and optimization processes.

  • Empowerment: The use of 5 Whys by individuals a positive culture that promotes a deeper understanding of systems and processes, empowering teams to take ownership and responsibility in addressing issues.

How to Conduct a 5 Whys Root Cause Analysis?

Step 1: Define the problem

This is an important step as if the problem is not defined effectively it could result in focusing in the wrong problem. A good method for this could be to use the 5W1H Is/Is Not Problem solving technique to gain a common understanding of that the problem is.

When stating the problem you are going to conduct a 5 Whys on it is important to be specific about the issue and avoid ambiguous descriptions. Additionally, where data and information is available this should be collected and used as evidence that points to the actual problem rather than opinions of the problem. 

Step 2: Ask the First “Why?”

Now you have a clear problem definition you should ask the question “Why did that happen?” This should be done to understand the problem without making assumptions and should be done with supporting facts and data that backs up the initial answer to the question.

Step 3: Continue to Ask Why?

Now you should have an answer to the first why. This should form the next step and ask why did that happen. This ensures you dont settle for the inisital surface-level answer or symptoms of the real problem and pushes you to understand the underlying issues.

When you continue to ask why you should:

  • Continuously question the previous answer
  • Challenge answer that seem like assumptions and lack evidence to support them to avoid going down the wrong route. 
An example of this for a website going down due to the server being overloaded might be  If the server was overloaded, the next logical question is, “Why was the server overloaded?” The answer might be “There was a sudden spike in traffic.”

Step 4: Continue the Process

You should continue the process of asking why until you get to the root cause of a problem which results a logical conclusion of the root cause of the problem which can be addressed. This may take 5 whys it could be more or less depending on the problem, 5 Whys is just a good average that gave the tool its name.
When doing this make sure you:
  • Keep the questioning focused on the problem
  • If you feel the questioning is going off track revert back to what the initial problem definition.
  • Ensure each answer provided logically leads to the next “Why?”
  • The 5 Whys process then concludes when further questions leads to no further valuable answers are given or the when the root cause of the issues becomes clear.

Step 5 Implement Solutions

Once you have identified the root cause the you need to address it by implementing a solution to prevent the problem reoccuring.

This should be a case of developing an actionable solution that address the root cause of the issue and not preventing the symptoms as addressing the symptom will likely cause the issue to reappear elsewhere.

Make sure you test the solutions to ensure they are effective in addressing the root cause, you should then continue to monitor the process over time to confirm the problem did not reappear in the same place or elsewhere.

If the problem does not re appear congratulations you have solved the problem!

An Example of 5 Whys Analysis

Below is a good example of a 5 Whys analysis done in a situation where there was a production downtime.

5 Whys Corrective and Preventive Actions Lean Six Sigma Tools Example of a 5 whys analysis bening done on production down time


To summarize, the 5 Whys process is an effective problem-solving tool that can assist businesses in identifying the root cause of a problem and developing effective solutions. Teams can delve deep into underlying issues and develop targeted solutions that address the root cause of the problem by asking “why” multiple times.

The five steps of the 5 Whys process – defining the problem, asking “why” once, asking “why” more times, developing a solution, implementing the solution, provide a clear framework for problem-solving and can help ensure that the problem is effectively resolved. The 5 Whys process encourages teams to think critically and systematically, resulting in long-term solutions that are effective, targeted, and sustainable.


A: The 5 Whys technique is a problem-solving method that involves asking “why” multiple times to uncover the root cause of a problem or issue.

A: The 5 Whys technique involves repeatedly asking “why” to identify the underlying cause of a problem. After asking “why” five times or until the root cause is revealed, you can develop effective solutions to address the issue.

A: The primary purpose of the 5 Whys technique is to identify and address the root cause of a problem. It helps organizations and individuals go beyond surface-level symptoms and understand the deeper issues affecting their processes or systems.

A: The 5 Whys technique is best used when you encounter a problem or issue that needs to be resolved. It is particularly useful for complex problems, recurring issues, or situations where multiple factors contribute to the problem.

A: Yes, the 5 Whys technique can be applied to any industry or field. It is commonly used in manufacturing, engineering, healthcare, software development, project management, and various other sectors.

A: While the technique is called the “5 Whys,” the number of “whys” you need to ask may vary. The goal is to keep asking “why” until you reach the root cause of the problem, which may require more or fewer than five iterations.

A: Yes, there are a few limitations to consider when using the 5 Whys technique. It relies on the skill and knowledge of the people involved, and it may oversimplify complex problems. Additionally, it assumes a linear cause-and-effect relationship, which may not always be accurate.

A: Yes, the 5 Whys technique can be used in a group setting. In fact, involving multiple perspectives can enhance the effectiveness of the technique and lead to more comprehensive problem-solving.


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Daniel Croft

Daniel Croft is a seasoned continuous improvement manager with a Black Belt in Lean Six Sigma. With over 10 years of real-world application experience across diverse sectors, Daniel has a passion for optimizing processes and fostering a culture of efficiency. He's not just a practitioner but also an avid learner, constantly seeking to expand his knowledge. Outside of his professional life, Daniel has a keen Investing, statistics and knowledge-sharing, which led him to create the website learnleansigma.com, a platform dedicated to Lean Six Sigma and process improvement insights.

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