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Is the “5 Why” Method Still a Useful Tool?

Is the "5 Why" Method Still a Useful Tool?

To solve anything other than a simple problem properly, you need to drill down through the symptoms to the underlying or what are often more commonly called the root causes. A simple but effective way to do this is to use the “5 Whys” technique. This is a relatively straightforward tool, but it can be a very powerful one.

The 5-why approach had its beginnings in Japan in the late 1940’s when Sakichi Toyoda, one of the fathers of the Japanese industrial revolution and the establishment of the car company Toyota. While the technique was used as only one part of its internal process improvement efforts inside Toyota, by the late 1950’s and 1960’s it gained wider recognition, throughout manufacturing in particular, on a worldwide basis in the early 1970’s. And as total quality, six sigma and lean methodologies gained international traction in the 1980’s and 1990’s , the 5-why method became a popular tool to deploy on an even more regular basis in many industries and especially in the safety incident investigation area in particular.

Despite this much increased reach, the use of this tool has been much less in evidence in the last 10-15 years but this may be more to do with the passing of time or “familiarity breeding contempt” rather than being about the tool losing its “edge”. It’s also true that even this simple tool can be poorly implemented, so in this brief article we will look at how the 5 why tool is best used and in what circumstances. 

On the surface, the 5 Whys technique is very simple: when a non-trivial problem or issue that needs to be tackled, the deeper sources of the problem are progressively uncovered by asking “why” five times (although teams may stop earlier at only 3 or 4 whys on occasions and may even ask more than 5 whys if they wish. The number “5” was chosen by Sakichi Toyoda because it was the most common point at which the deeper and more human cause was discovered.

So let’s look at a simple example:

Problem: A customer is complaining about the very late delivery of a product you manufactured.

  • Why? The time to deliver was double what it usually takes.
  • Why? The manufacturing process took much longer than we expected.
  • Why? We were waiting on critical materials from a supplier.
  • Why? The supplier’s major raw material sourcing partners failed to deliver.
  • Why? They were experiencing major shipping delays and did not inform anyone of this.

Response: We need to have alternative suppliers of this raw material and a better communication system.

As we can see, this response is to the deeper why issues surfaced at the fifth why and not at the first or second, when we may have been tempted to look at our internally manufacturing efficiency and effectiveness when the real root causes were at the supplier’s door (question 4) and in a communication system that had failed (question 5)

How to Best Use the 5 Why Approach

Before using the 5-why approach it is worth a session leader or facilitator reading about the technique and learning more about best-practice ways of applying it. For example, facilitators need to learn that “why” questions are best asked gently with lots of careful listening to the responses at each stage. In addition, responses at each “ask” of the question may have multiple possible causes and it may therefore be necessary to follow more than one line of thought. For instance, to a question such as “why did the employee slip and fall”, a response might be “because the floor was wet and he was running.”  The next level of whys may consequently need to follow both why it was wet and why he was running, as different threads here. The other factor that needs much care for a facilitator is learning to ensure that asking questions is done without getting into “finger pointing” or assigning blame (which can easily happen). The ultimate goal is to identify underlying causes that can be fixed at a system level and NOT to apportion blame to individuals. In fact, a good starting point is to say that any mistakes or problems we deal with in general are the fault of the whole organization and its systems, not any one person.

Having identified a problem or an issue about which there is concern, the very first “ask” is usually “why is this problem or issue occurring?” Here, the responses should be calm and fact-based before we ask the next “why” again. We then simply continue with this “why” asking process until you reach the root cause(s) of the problem or issue, at which point you can start to discuss a possible solution which stops it or prevents it recurring.

Session leaders are best served by keeping notes of what is said and to give people plenty of time to brainstorm at each “ask” of the “why” question. Sometimes this is a straightforward and linear affair but in a complex problem situation each layer may need lots of discussion to surface all the possibilities before moving on.

By repeatedly asking the why question we are essentially very slowly peeling  away the layers of an issue, just like the layers of an onion, using the last response to open up one or more issues that may be been obscured before. The real key here therefore is to avoid going into these discussions with any assumptions, biases or unfounded beliefs (as much as this is possible) and encourage people to stick to facts and evidence and drill down to the deeper issues.


The five “why” approach will not work for every problem (for example it is less effective with emotional issues and soft subjects with little hard evidence such as “why are the values in this team so at odds?”) but it works for most of them if applied carefully and people do it often to see the benefits. This regular practice approach also overcomes the fear that the process will be used to apportion blame. It is therefore crucial to make sure that the solutions at root causes level propose system-side changes and not ones that punish a person in any way or treat an issue as a mistake only to be fixed by penalizing the perpetrator. To use the example above, even when someone slips and falls when running the long-term solutions are almost wholly on the system side (in this case with floor integrity, training and management direction for example) and not with the unfortunate person who fell. What he or she has actually done has provided a great learning opportunity to prevent him or her and others from falling in the future.

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About Dr. Jon Warner

Dr. Jon Warner is a prolific author, management consultant and executive coach with over 25 years experience. He has an MBA and a PhD in Organizational Psychology. Jon can be reached at

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One Comment

  1. Rob JonesSeptember 26, 2016 at 12:19 pm

    Discussions of the 5 Why’s often fail to recognize the origin of the technique to the organic discovery process of very young children. Any 5-year old would tell you it’s still a useful tool.

About the Editor and Primary Author

Jon Warner

Jon Warner is an executive coach and management consultant and in the past has been a CEO in three very different companies. Read more

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