5 Whys

Getting to the Root of a Problem Quickly

Learn how to drill down into a problem,
to get to its root and solve it quickly and effectively.

Have you ever had a problem that refused to go away? No matter what you did, sooner or later it would return, perhaps in another form.

Stubborn and recurrent problems are often symptoms of deeper issues. A "quick fix" may seem convenient, but it's really just a temporary solution and it may solve only part of the problem.

To solve it properly, you need to drill down through the symptoms to the underlying cause. This article looks at Sakichi Toyoda's 5 Whys technique – a simple but powerful tool for quickly uncovering the root of a problem, so that you can deal with it once and for all.

About the Tool

Sakichi Toyoda, one of the fathers of the Japanese industrial revolution, developed the technique in the 1930s. He was an industrialist, inventor and founder of Toyota Industries. His technique became popular in the 1970s and Toyota still uses it to solve problems today.

Toyota has a "go and see" philosophy. This means that its decision making is based upon an in-depth understanding of the processes and conditions on the shop floor, rather than reflecting what someone in a boardroom thinks might be happening.

The 5 Whys technique is true to this tradition, and it is most effective when the answers come from people who have hands-on experience of the process being examined. It is remarkably simple: when a problem occurs, you uncover its nature and source by asking "why" no fewer than five times. Here it is in action:

Problem: Your client is refusing to pay for the leaflets you printed for them.

  1. Why? The delivery was late, so the leaflets couldn't be used.
  2. Why? The job took longer than we anticipated.
  3. Why? We ran out of printer ink.
  4. Why? The ink was all used up on a big, last-minute order.
  5. Why? We didn't have enough in stock, and we couldn't order it in quickly enough.

Counter-measure: We need to find a supplier who can deliver ink at very short notice.

When to Use the Tool

You can use the 5 Whys in troubleshooting, quality improvement and problem solving, but it is best for simple or moderately difficult problems.

For more complex or critical problems, it can lead you to pursue a single track of enquiry when there could be multiple causes. Here, a wider-ranging method such as Cause and Effect Analysis   may be more effective.

This simple technique, however, can often quickly direct you to the root of the problem. So, whenever a system or process isn't working properly, give it a try before you embark on a more in-depth approach.

The simplicity of this tool gives it great flexibility, too, and it combines well with other methods and techniques. It is often associated with lean manufacturing   (also part of the Toyota Production System), where it is used to identify and eliminate wasteful practices. It is also used in the analysis phase of the Six Sigma   quality improvement methodology.

How to Use the Tool

The 5 Whys is a simple, practical tool that is very easy to use. When a problem arises, simply keep asking the question "why" until you reach the underlying source of the problem, and until a robust counter-measure becomes apparent.

Note:

The 5 Whys uses "counter-measures," rather than solutions. A counter-measure is an action or set of actions that seeks to prevent the problem arising again, while a solution just seeks to deal with the situation. As such, counter-measures are more robust, and are more likely to prevent the problem from recurring.

Each time you ask "why," look for an answer that is grounded in fact: it must be an account of things that have actually happened – not events that might have happened. This prevents the 5 Whys becoming just a process of deductive reasoning, which can generate a number of possible causes and, sometimes, create more confusion.

Keep asking "why" until you feel confident that you have identified the root cause and can go no further. At this point, an appropriate counter-measure should become evident. If you're not sure whether you have uncovered the real root cause, consider using a more in-depth problem-solving technique like Root Cause Analysis  .

Key Points

The 5 Whys strategy is an easy to use, effective tool for uncovering the root of a problem. You can use it in troubleshooting, problem solving and quality improvement initiatives.

Start with a problem and ask "why" it is occurring. Make sure that your answer is grounded in fact, then ask "why" again. Continue the process until you reach the root cause of the problem, and you can identify a counter-measure that prevents it recurring.

Bear in mind that this questioning process is best suited to simple to moderately-difficult problems. Complex problems may benefit from a more detailed approach (although using 5 Whys will still give you useful insights.)

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Comments (22)
  • Michele wrote This month
    Hi serpiro,

    The 5 Whys technique arose out of the Japanese industrial revolution as a tool to improve quality and productivity on production lines. As with all quality improvement tools, data needed to be factual (observable and repeatable) for it to be usable. You're right in saying that the 5 Whys is not appropriate in determining the causes of conflict or people related issues. Human dynamics are situational and complex and do not lend themselves to cause and effect analyses.

    Michele
    Mind Tools Team
  • serpiro wrote This month
    I see two problems with this techique: first, it should be based on facts, not in assumptions; second, it is designed to operational problems, not those related to conflicts or relationship prolems on the work enviroment.
  • NainaMT wrote This month
    Helpful to root cause the problem which occurs due to not following predetermined process flow / procedure correctly. And make understand the responsible person....
  • NMThompson wrote Over a month ago
    Very helpful for problems that are not to complexed
  • Ali wrote Over a month ago
    Thanks for sharing.
  • James wrote Over a month ago
    Hi Everyone

    We've given this popular article a review, and the updated version is now at
    http://www.mindtools.com/community/pages/article/newTMC_5W.php

    Discuss the article by replying to this post!

    Thanks

    James
  • MichaelP wrote Over a month ago
    Judestar23 hi so we agree on the intention:

    The "5 whys" helps to move past assumptions and get to the truth.

    And the origin: A very good technique used by 2 and 3 year olds

    Now to the crux of the matter and the HUGE opportunity: However I think in the workplace you can't just wrap up the conversation in exasperation by saying "Just because!!" It is good to put thought into why a situation has developed or occurred so that lessons can be learned and similar mistakes avoided.

    Creating the 'learning organization' is the goal for many and its a tough reality. Companies just what to grow, win more customers, and finding the time to learn and engage their employees is often hard to do.

    Thank you for sharing and please keep us posted on your progress.

    cheers Michael
  • judestar23 wrote Over a month ago
    A very good technique used by 2 and 3 year olds Thay seek to gain a better understanding of the world around them and challenge the adults in their lives to come up with genuine reasons "WHY?!" However I think in the workplace you can't just wrap up the conversation in exasperation by saying "Just because!!" It is good to put thought into why a situation has developed or occured so that lessons can be learned and similar mistakes avoided. The "5 whys" helps to move past assumptions and get to the truth.
  • fxgg090 wrote Over a month ago
    This is a very important question, simple but relevant. It´s also used in Science a lot: Why this thing happens, why this cell moves, why why why why ....lot´s of why to get insight and explanations.

    It gives conscience to the other person to analyze and reflect the situation and in some way to project responsibility.

    The only problem is when they use the why to the leader... Why don´t you pay us more? that would be an extremely difficult question. Or why don´t you let us have more lunch and such complains.

    I like the why, I use it and have deep insight on the person his feelings, his view and I find most of the time they have the answer Im looking for.

    Francisco X G .
  • Dianna wrote Over a month ago
    Interesting point rayfih and agree that in a coaching situation, asking "why" would get you defensive remarks. For those sorts of conversations I really like the technique of coaching with feedback (http://www.mindtools.com/community/pages/article/newTMM_21.php) . That's where you ask questions to help the person gain insight into their behaviour or decision. Interestingly, the example conversation in the article uses a few "whys" but not in the context of, "Why did you do that" and instead, "Why do you think that happened?". A subtle but significant difference.

    Dianna
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