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5 Whys

Getting to Root Causes, Fast!

Asking why 5 times: “the 5 Whys”, is a simple but powerful tool to use with any problem solving activity. It’s a technique to help you get past the symptoms of a problem, and to find its root causes. Simply ask the question “why” up to five times. Of course, there’s no magic in this number of questions.

It may take six or it may take three. The important thing is that you use this  most powerful of words to peel away the layers that envelope any problem. It’s so simple, even a child could use it – and they do! This may look familiar to many of you:

“Why do I have to go to bed?” – “Because you need your sleep.”

“Why do I need to sleep?” – “Because it’s good for you.”

“Why is it good for me?” – “Because your body needs regular rest.”

“Why does my body need rest?” – “Because resting helps you re-charge your battery.”

“Why do I need to re-charge it?” – “Because otherwise you’d have no energy to enjoy tomorrow.”

Of course, those of you with children will see the flaw in this analogy. If only they stopped at 5 whys!

5 Whys

When faced with 5 Whys, our first answers usually address the obvious aspects of a problem or situation. When repeated, the question prompts us to think more deeply about why something may have happened.

The aim of deeper questioning is thus to ensure the problem is fundamentally examined and then solved. This is a simple but effective tool to help you find the root cause of a problem, and take action.

In this article we explain the 5 Why technique – its benefits, how to use it, and how to overcome some of its limitations. We also include links to our free problem solving resources, our management tips, and to other key links on the web.

Ask and You Shall Receive!

The essence of 5 Whys is quite simply to ask “why?” 5 times. This example from The UK’s National Health Service Improvement Network is a good illustration of this technique in action:

(there are further examples on the resource links at the bottom of this page).

The patient was late in theatre. Why?

There was a long wait for a trolley. Why?

A replacement trolley had to be found. Why?

The orginal trolley’s safety rail was worn and had eventually broken. Why?

It had not been regularly checked for wear. Why?

We do not have an equipment maintenance schedule…

Setting up a proper maintenance schedule helps ensure that patients will never be late again due to faulty equipment. If we just repair the safety rail, or even do a one-off safety rail check of all trolleys, the problem will happen again at sometime in the future.

So Why Use 5 Whys?

Its beauty is in its simplicity. It is a tool which everybody can readily apply. It also ensures that you don’t move to action straight away without fully considering whether the reason you’ve identified really is the cause of the problem.

What Do You Do to apply the 5 whys technique?

The  5 whys tool can be used by individuals but it’s probably best used as a team problem solving tool. When a problem or issue has occurred a team session could help get to the cause of the problem. The benefit of a team approach is that you can involve the people who probably know most about the situation you’re investigating.

Use a flip chart to gather the group’s ideas:

  • State the problem or issue that you are trying to resolve.
  • Check that everyone agrees that this is the problem.
  • Seek any data you can use to illustrate the problem?
  • Ask the first question “why”. “Why do you think this is happening?” or “Why did this happen?”
  • Encourage the team to work in small groups to generate possibilities.
  • Ask the second “why” and so on.

Summarise and clarify as you go to ensure that each possible reason is understood. Identify other evidence and data or information collection techniques which could confirm or eliminate the proposed cause of the problem.

What are the limitations of the 5 whys technique?

It’s probably best to use the 5 Whys technique with a range of other approaches. Especially think about using techniques which enable you to verify possible causes with evidence and data.

The technique is considered to have limitations because:

  • Participants in the process may not delve deeply enough in attempting to identify root causes.
  • The process may be limited by the knowledge of the person(s) carrying out the technique.
  • Different people will often get different answers using the technique, raising questions about its reliability.

To overcome some of these issues:

  • Develop facilitator skills to ensure that the process is robust and all participants contribute and investigate each of the possible whys.
  • Use the approach with other techniques. Particularly with data gathering techniques which may help you cross-check your findings.
  • Use the 3 Whos to answer the 5 whys! In our Best Management Tools article, we recommended the advice of Reg Revans, best known for his work on action learning. He suggested three simple but powerful questions to use when investigating situations or problems. Ask yourself:
  • Who knows? (about the situation, or who has most of the information we need to solve it/realise it)
  • Who cares? (that something is done about it)
  • Who can? (do something about the solution)
  • These questions help to identify the people you need to overcome problems or to realise opportunities. Ensure you have the right people together to ask the 5 Whys.

A final, crucial point comes from Teruyuki Minoura, once Toyota’s managing director of global purchasing. Toyota is where the 5 Whys Technique was originally developed and Minoura advised that, to make the technique effective, you need well trained staff. The technique depends on what people know.

Develop knowledgeable people in your organisations, who know your processes inside out, and are continually improving their area of expertise. Minoura warns about the dangers of deduction in the process, and suggests it should be countered by observation. Is that what is actually happening? Using well trained staff to implement a 5 Whys analysis is essential for its success.

Problem Solving and 5 Whys Links and Resources

The 5 Whys technique is a simple and effective problem solving tool, which you may want to use with some of our other free problem solving tools and techniques.

The overall problem solving process is captured in our seven step problem solving technique. This is the best starting place, giving you a problem-solving overview, and a structured process to follow. The 5 why technique fits into the analysis stage of the process.

Our other problem solving tools include:

The Best Management Tool Ever - A Good Question. This gives useful advice on how to use questions effectively as a management tool. It includes a tool for exploring the potential of new opportunities.

Problem Solving Skill - Finding The Right Problems To Solve. One of the most important lessons about problem solving is to choose problems worth solving! Here’s a tool to show you how.

Problem Solving Activity. Provides a structured set of questions to help you define and analyse problems.

Problem Solving Technique - 4 Steps to Improve Your Processes. This guides you through option generation and selecting appropriate solutions.

The Power of Positive Thinking - 5 Questions to Transform Problem Solving. This tool encourages you to view problems differently. Not only do we need to find the right problems to solve, we also need to see problems as opportunities. What opportunities will solving this problem create? How do you do that? The Power of Positive Thinking provides some answers, by asking opportunity creating questions.

UK Health Improvement site. The site provides a short explanation of the technique with some straightforward examples. There is also an excellent range of problem solving techniques explained on the site.

The Toyota Production System, from which the 5 Why technique has been developed, is explained in this article. In particular there is a good explanation of how to make the 5 Why technique work effectively.

Wikipedia - 5 Whys, provides more background and explanation of the 5 why technique.

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