5 Whys – What It is and How To Use It

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Work Out the Root Cause, and Take Measures to Put Things Right

5 Whys is a simple, and to the point, problem-solving method, that explores the underlying cause and effect of problems. Its primary goal is to determine the problem’s root cause by successively asking the question “Why?” and coming up with answers and solutions.

What is 5 Whys?

So 5 Whys gets its name from the widely accepted belief that asking ‘why?’ five times is usually enough to reveal all you need to know to solve the problem. Some problems may need more or less than 5, depending on the depth of the root cause, but you can take five as the general rule of thumb.

What Does 5 Whys Teach?

In a nutshell, this method helps with

  • Defining the problem.
  • Setting goals for countermeasures.
  • Analysing the root cause.
  • Establishing countermeasures.
  • Checks, standards, and follow-up activities.

What Are the Benefits of Five Whys?

  • Helps identify the root cause of a problem.
  • Determines the relationship between different root causes.
  • Shows how one process can cause a chain of problems.
  • Proves highly effective without needing more complicated evaluation techniques.

There are problems where more complicated evaluation techniques are necessary. We’ll look at those briefly at the end. For now, let’s focus on what you can achieve with 5 whys.

Lady holding a sign with 5 whys
Achieve results with 5 whys


In the simplest situation, say a piece of equipment fails and a part is replaced. Here, the cause is immediately apparent, and you can take steps to remedy it. That sounds fine, but if it fails again and you don’t investigate it, there could be another underlying problem.

With 5 Whys, the specific number five isn’t really the point. As we said, some problems may need more or less than 5. Now what’s important is to keep asking until you reach the root cause and eliminate it. However, where the problem is more significant, there could be wider implications that need to be understood and addressed, and you might uncover a chain of connected reasons.

Using 5 Whys will help you find the root cause, and do something about it

Now here’s something else to think about. As you do your analysis, it may eventually emerge that human error is the cause, and either an individual or various people may be responsible. That said, 5 Whys is essentially about assessing the process that’s led to the problem, rather than the people. And this is a recurring point in this article. You need to bear in mind that even if it turns out there is human error and people are responsible for what’s happened, it’s not necessarily the fault of the individuals, but what they’re being asked to do and the equipment they’re given to do it. We’ll explore this as we go on.

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Where Did the 5 Ways Come From?

The software experts Tulip Interface say on their website that the 5 Whys method was originally developed by Sakichi Toyoda, the founder of Toyota Industries. Actually, it became widely used by the Toyota Motor Corporation and is still used frequently now.

Taiichi Ohno is the architect of the Toyota Production System, which is based on the philosophy of achieving the complete elimination of all waste in pursuit of the most efficient methods. He describes 5 Whys as the basis of Toyota’s scientific approach. All in all, it boils down to “go and see for yourself,” and from there, understand and solve problems faster and more effectively. 5 Whys is lean, to the point, and practical.

The 5 Whys method is rooted in the hard-headed world of manufacturing, rather than what some folk regard as the ‘woollier’ fields of psychology and social research. This field of endeavour has given us much of our knowledge of such things as leadership styles and motivation. In fact, psychology does play a part in some work problems that the 5 Whys can analyse, but let’s park that thought for the moment.

When Should You Use the 5 Whys?

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Now it won’t work for everything


We mentioned Tulip Interface just now. They’re a software development company based in Somerville, Massachusetts, that works across the industry sectors. And on their website, they suggest this is when to use 5 Whys:

  • For simple to moderately difficult problems.
  • More complex problems may require this method in combination with some other problem-solving techniques. We’ll come back to this. You might also like to read our article on Problem Solving.
  • When problems involve human factors or interactions: That means any time human error is involved in the process. However, as we said earlier, you need to bear in mind that the process itself, or the technology, may be causing human error.

Key Things to Keep in Mind When Using 5 Whys:

  • Distinguish the root causes from the symptoms or causal factors. We’ll come back to this in a moment.
  • To make sure you are attributing the correct answer to each “Why,” try working backwards. In each case, be certain you answer the “Why?” part in response to the problem identified for that question.
  • Break down your answers as much as you like, the more the better. You can have many more than 5 Whys if it helps!
  • Make sure you always base your answers on facts and data.
  • Last, but not least, focus on assessing the process, not the people. We’ve established this point now, don’t lose sight of it.
This next bit is important. To get the best from 5 Whys, you need to distinguish between root causes and causal factors
  • A causal factor is a major unplanned, unintended contributor to an incident, a negative event or an undesirable condition. It’s something that, if you eliminated it, would have either prevented the incident from occurring or reduced its severity or frequency. Causal factors are also known as critical causal factors or contributing causes.
  • A root cause is a fundamental reason for the occurrence of a problem or event. This is the difference between the root cause and the causal factors. Analysts can look for the root cause of an event, to prevent it from happening again in the future.

Now having cleared that up, let’s look at how to use this method to solve a problem.

How to Complete a Five Whys Root Cause Analysis

Man with paperwork doing analysis on 5 whys
Get the steps


To do this, you need to write things down as you go:

  1. Begin by pinpointing the problem. Be clear about exactly what it is that you’re having an issue with. Identifying this will help the whole team focus on finding answers.
  2. Ask why the problem happened, and write the answer down below the specific problem you stated in step one. Now ask why that happened, find the answer, and so on.
  3. Keep asking “why?” to each of the successive answers you write down until you reach the root cause of the problem.
  4. As we said before, this may take more or less than five whys. Don’t worry about that. What matters is that you make sure your team sees eye-to-eye with each of the questions being answered and that you all agree that you have correctly pinpointed the final root cause.

So we said earlier that the aim of 5 Whys is to assess the process that’s going wrong, not the people.

Let’s Hear It From the Experts…

Human error isn’t necessarily a human problem. Actually, the root cause could be a problem with your work systems. This is a conclusion Tulip Interface comes to on their website. They quote a study sponsored by ServiceMax from GE Digital, which found that 23 per cent of all unplanned downtime in manufacturing is the result of human error.

Tulip point to a growing body of research in psychology and organisational studies that, they say, has changed how we think about workplace mistakes. They go on to say we now know that most individual errors happen when systems make human error likely, or even inevitable. In their view, human error goes along with a lack of flexibility to augment worker processes in manufacturing. Implementing tech which delivers that flexibility, clearly involves training.

The wider point is, you can also use the 5 Why’s to solve problems of various kinds which arise in office environments. People in office-based and remote settings are working day in and day out with applications like email, Excel, Zoom, Teams, WordPress, accounting packages, HR software, customer relationship management (CRM) systems and so on.

If you’re running a company with all these functions, the root cause of a problem may turn out to be that people are having difficulties with the tech you’ve given them. You may need to ‘augment your worker processes’ by training them on it, rather than expect them to work out how to use it themselves. It might turn out that coaching them could be transformational.

You May Also Hear People Talking About 5 Whys and 1 How, and 5 Whys and 5 Hows. Don’t Be Confused!

Confused girl on wrong or right 5 Whys
If you’re confused, don’t be


The Five Why’s and 1 How:

Quality Systems Toolbox is an ISO compliance management system for businesses. The people behind it are based in Australia and have built their business on solving problems. On their website, they have their own insight on 5 Whys, to which they add one How? As they put it, this is an attempt at addressing the root cause of the issue by asking, how do we fix this problem once and for all? In other words, what countermeasure do we need to take?

The 5 Whys and 5 Hows:

This s another way of looking at this, the ‘how?’ bit again meaning how do we fix it? Each time you ask why this is happening, as we’ve been saying, you will identify a causal factor. Be aware though, you may be able to fix each of the causal factors with a countermeasure, hence the 5 hows, but you may not get to the root cause.

How to Use the 5 Whys Method

  1. Assemble your team. Ensure that as many people with different perspectives are included as possible, so you zero in on the right questions.
  2. Pick a facilitator for your meeting. See our article on facilitation techniques.
  3. Define the problem.
  4. Ask ‘why’ five times. Answer each question quickly to avoid going down rabbit holes and jumping to conclusions.
  5. Address the causal factors and the root cause and assign responsibilities to people for coming up with countermeasures and implementing them.
  6. Monitor your countermeasures. It’s important to monitor how effectively your countermeasures solve or minimise the problem. If nothing changes, you may have identified the wrong root cause, and you need to go through the 5 Whys again.

As you go through the process, you may find someone has dropped the ball along the way. Rather than placing blame, remember that the point of all this is to find out why the process failed. Use this line of questioning to find what you need to fix.

Here Are Some Examples of How People Use the 5 Whys in Business

1. Marketing:

Marketers can use root cause analysis to find out why sales are declining. It could be declining consumer satisfaction with the customer support team. If that’s the case, the company can carry out focus groups with customers to establish if this comes down to a lack of product knowledge, unfriendly or unresponsive reps, and long wait times.

2. Retail:

A retailer notices their shelves are frequently out of stock, and carries out root cause analysis. It may be that the ordering process is inadequate, leading to frequent ordering delays. As a result, the store implements a new ordering process to eliminate delays and keep shelves fully stocked. Or there could be problems at the distribution centre, which they then analyse

3. Food Service:

A restaurant encounters recurring food safety issues. They work through the 5 Whys and find that employees lack adequate training in food safety procedures. As a result, the restaurant implements additional training and oversight to ensure compliance with food safety regulations and prevent future issues.

And Finally: Know the Limitations of 5 Whys

Disappointed lady with danger levels icon in background
Finally, don’t become disappointed when you know the limits


  • The person leading the 5 Whys analysis needs to have expert knowledge about the problem and the possible issues. Because if they don’t, the method may not lead to finding the root cause.
  • If you’re going through this with a team, your success relies heavily on the skill of the facilitator. One wrong answer may throw the questioning out completely, leading to a wrong conclusion.
  • The 5 Whys method assumes that the ‘presenting symptoms’ all stem from a single root cause. But with complex problems, this isn’t always the case. Actually, a 5 Whys analysis may not reveal all the causes tied to the symptoms. That’s because the 5 Whys by themselves are unable to differentiate between causal factors and root causes. Hence, there can be a lack of rigour, if the people using it aren’t being made to check if they’re right about the root causes generated by the method. How successful 5 Whys is in each case depends, to a degree, upon the skill with which people apply it.
  • People using the 5 Whys often make use of the “countermeasures” aspect, addressing each why, rather than finding the root cause. Yes, countermeasures are a robust way of solving problems, but they don’t necessarily prevent the root cause problem from reappearing. You need to do both things – address the symptoms, and find the real solution for the root cause.


A root cause analysis method like 5 Whys helps you to discover the underlying or systemic problem, rather than the immediate causes, or causal factors. So if you only correct an immediate cause, you may eliminate a symptom of the problem, but not the problem itself, and you’ll have to go through the process all over again. Good luck!

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