The 5 x Why Method (The 5 Whys)

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Ger de Waard
Management Consultant, Netherlands

The 5 x Why Method (The 5 Whys)

The "5 x why" method has been developed by Toyota to perform an iterative Root Cause Analysis of production-related problems. The "5 x why" method is one of the available tools for performing a root-cause analysis. Its simple design and effective output made the 5 x why method also into a popular method used in Kaizen, Lean Production, Six Sigma, Value Stream Analysis, etc.

  • IDENTIFY THE PROBLEM for which the root cause has to be identified.
  • ASK: WHY has this problem arisen? The result is a reply with a new or different problem.
  • KEEP ASKING: WHY? Take the first answer (or problem) and reformulate the question: Where has this issue has arisen? Repeat these steps until you arrive at the core (root-cause) of the issue/problem.
The 5 x Whys can be used for several things:
  • VALIDATING ASSUMPTIONS: It is a simple tool that helps the Belt to unearth an assumption embedded in the process he/she is investigating. Once an assumption is revealed and of course also tested with data, it ensures excellent results.
  • DETERMINING ROOT CAUSES: However 5 x Why is more used in determining the Root Cause(s) of problems
    This technique is most used in the Analyze phase of DMAIC (Define, Measure, Analyze, Improve, Control). The 5 x Whys doesn’t involve a statistical hypothesis and in many cases can be completed without a data collection plan.
  • FINDING NON-VALUE ADD ACTIVITIES: The 5 Whys can also be used as a tool in Value Stream Analysis. Value stream mapping is as we know hard work because it requires looking at a process as if every step is non-value-added and is costing the organization time and resources. The 5 Whys is an easy way to root out as many non-value-added steps as possible.
Often you need to ask 6, 7 and even sometimes 8 x Why to find the real root cause of the problem. Perhaps a better name would be "Multiple Why’s Method".

An excellent example of 5 x Why is the Jefferson Memorial by Juran Institute.

  Ashok Kella
Manager, India

Our Endorsement to the 5 Whys

Yes, recently, in a complex issue dissecting in our organisation, unaware of the 5 Whys theory, we solved the issue to rescue and move towards the goal, but we move on and on down to the every outcome...

  David Week
Director, Australia

Better, but not 'root'

Five Whys is a great way to get better answers, but I think that’s it's a problem to call the result THE "root" cause—especially for Western-trained managers, who are culturally trained to think one c...

  Ivan Kohlinsky
Management Consultant, United Kingdom

Back to Fundamental Thinking

Excuse me, but I am asking myself WHY is this method thought of as new, useful and fundamental, as it is. This method along with such methods as PABLA (problem analysis by logic approach), used by the...

  Dr. Schoenborn
Management Consultant, Germany

5-W in Combination with Impact Measurement

I agree with @David that 5-W is a good approach for root-cause-analysis, but you should be aware that there could be several causes. For that reason I combine 5-W always with a Fishbone-diagram and m...

  Wulf-Dieter Krueger
Teacher, Thailand

5 Times Why - the Emperor's New Clothes

Watch your children asking this question again and until they are satisfied with the answer. This method is no rocket science. However, adults in academia might have forgotten about it. This seems t...

  Paramathmuni srinivas Kumar

Root Cause by Conscious Approach

A rational approach is certainly a way to get clarity, however could there be other ways also? For example, what if a person has worked on his inner tendencies which conflict on each other and is succ...

  David Torres
Manager, Mexico

5 x WHY’S is not Enough for Me

I took an 8D’s course and the homework was to take a real actual client customer complaint, so my team and I started working on it. Even if I had all company resources to try to find the root cause an...

  Johnny Michael Tan
Management Consultant, Malaysia

I Prefer the Following Name for this Tool: Why-Why Analysis

I want to share that when my Semiconductor manufacturing site was pursuing Total Productive Maintenance (TPM) we were introduced to this tool by our Japan Institute of Plant Maintenance (JIPM) Consult...

  Rodolfo Dionisi

Tools According to Problem Complexity

Remember that the first step to solve a problem (or to be more precise, to have reasonable chances of success) is to DEFINE THE PROBLEM AND ITS COMPLEXITY. After determining the problem’s complexity, ...

  Paramathmuni srinivas Kumar

Role of Biases in Determining the 5 Whys

The 5 Whys as a tool is available for long and is available everywhere. Why is it not effective as it should be in developing nations? And even in developed countries it is not effective at all times?...

HR Consultant, Belgium

1 WHY is Enough Sometimes

@Srinivas: There is always a WHY... Why this situation, why this conflict, why this feeling... But if you are clear in consciousness, you will get to the root cause with 1 WHY only instead of 5 or mor...

  Pedro Monteiro
Manager, Portugal

5 Why is Excellent Tool to Start and Get Back to the Basics

5 Whys is one of the best, simple and effective problem solving tools. Is it not enough?! Yes, sometimes it isn’t, but as a first approach to a problem which you don't know its depth it is excellent....

  Paramathmuni srinivas Kumar

Preparing for Usage of 5 Whys

Before we use the 5 Whys is it possible and useful to try to reduce any biases by preparing at different levels of human personality? What if such preparation is simple and takes 20 minutes of time p...

  VILMA JOY VALLE, Philippines

You Can Use 1 Why or 5 Whys or Multiple Whys

Not all people can solve a particular problem with just one "why". And not all problems, even how knowledgeable or experienced you think you are, can be solved with just "one" why. Therefore you hav...

  Ashok Kella
Manager, India

Change 5 Why into Why-why Analysis

@Johnny Michael Tan: I agree with you that "Five" is symbolic; the introducer has intended to make you ask why again and again till you reach at the root cause. So Why-Why seems to be a more appropria...

  Dietmar W. Sokowski
Consultant, United States

Back to Fundamental Thinking

@Ivan Kohlinsky: Good point Ivan. Your comment is ever so true. Similarly, the 7-Ws have been around for a long, long time, yet in some articles they are touted as "new". Likewise, "agile" thinking ha...

  Sudheendra G. Mudikeri
Management Consultant, India

A Tip for this Fundamental Why-Why Technique

No matter how many WHYs are used, this tool has withstood the test of time as an effective one for ROOT CAUSE ANALYSIS. When I speak about this topic to freshers in the industry, I stress the fact th...

  Olaf de Hemmer
Business Consultant, France

Why? or: What For?

I agree with pointing out that 'root cause' is helpful in solving certain problems. Causality is at the heart of the 'cartesian' way of thinking, the basis of scientific reasoning. But the majority o...

  C.L. Kappagomtula
Professor, Malaysia

Even a Single 'why' Can Suffice, Without Overtly Asking 'Why'

Those of you working in production/operations might have come across this situation several times, and resolved the problem 'hitting' at the very 'root' of the problem. The first Why can be an overt ...

  Miguel Sacramento
Business Consultant, Brazil

5 Why is not Japanese

@Wulf-Dieter Krueger: Yes. Every children has a "multiple why device" already built-in....

  Bevis Qiu

Find the Most Cost-Effective Solution after 5 Whys

Different solutions can be found through different Why questions. I think we might then compare the costs of them in order to arrive at the most efficient solution....

  Olaf de Hemmer
Business Consultant, France

Children Ask Why? Meaning what For?

@Wulf-Dieter Krueger: Are chidren not more interested in understanding the meaning / purpose of things (what for?) than their cause (why?)?...

  Miguel Sacramento
Business Consultant, Brazil

5 Why is not Japanese

@Olaf de Hemmer: Sometimes yes. It depends on each case. For instance, "Why are you prohibiting this?" and "Why did it brake?" questions are made with different purposes: effect (consequence) or cause...

  Wulf-Dieter Krueger
Teacher, Thailand

Children Asking Why

Children ask why for the same reason as anybody else in management or in a company: there is a problem at hand, because something is not being understood properly. And they will stop asking, when the ...

Manager, Nigeria

5 WHY Methodology is Advanced

The 5 WHY methodology for problem solving is more advanced than the perspectives of some others discussing it. Conducting 5 Why to solve problems in an organisation requires a multidisciplinary team w...

  Ashok Kella
Manager, India

Advanced 5 WHY Methodology

@FASESIN David: The effectiveness of Why-Why has been evaluated in combination with GEMBA, GSTD and OPL along with multidisciplinary team involvement. We have been discussing its effectiveness in its...

  Paramathmuni srinivas Kumar

Organisation Service or Product Delivery - Human Analogy-Root Cause

When we considering an organization as a living being, then there is always a relation to the mind, irrespective of the problem that a particular organ is experiencing. For example, an organization’s...

  jorge anibal hoyos hoyos
Manager, Colombia

Ask as Many Whys as Necessary

When talking about WHYS I also recall my kids when they were young asking all the time "WHY PA?" I think there is no mandatory quantity of WHYS; one should just ask as many WHYS as necessary. That mus...

  Paramathmuni srinivas Kumar

Conscious Approach

We have expert systems which are currently under development which use artificial intelligence and feedback loop mechanisms. To me they will be capable of finding the root cause quickly and accurately...

  VILMA JOY VALLE, Philippines

Methods of Iterative Root Cause Analysis

We have a lot of tools available in the past and at present to solve problems. This includes the use of “5 Why’s or “The Multiple why’s”. Perhaps one of them (5 Why’s or the Multiple 5 Why’s) could be...

  Lee, Youngki
Consultant, Korea (South)

My Important Experience with 5 Whys

I engaged a company in a training meeting with employees. They raised a major concern that the current company was facing. It was a challenge of a difficult problem to solve. We used the “5-why method...

  Paramathmuni srinivas Kumar

Delegation of All Rationally Viable Methods

If all rational methods including why why approach which can be automated and performance is better then is it not a better way to realize the human potential by using conscious based approaches?...

  Olaf de Hemmer
Business Consultant, France

AI and Causes / Goals

@Srinivas: I'd be curious to see how AI gets the answer to "why?": the 'cause' may be possible to find in past data, but how can you trace the goal without asking real people?...

  Paramathmuni srinivas Kumar

Feedback Loop Mechanism

Using semantic web technologies which are based on artificial intelligence it is possible to interpret what the result means. Using feedback loop mechanism it is possible to go into root cause. Wisdom...

  C.L. Kappagomtula
Professor, Malaysia

Stochastic Approach to Root Cause Analysis May Be the Need of the Day

I fully concur with Ger De Waard's argument to not restrict to 5 Whys alone. There is no real sanctity in this number of Whys, for the root cause is not a function of a fixed digit number of whys. Ma...


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