The five whys technique: what it is and how it is used

There are many problem-solving techniques out there, all of which are very useful depending on the type of problem you are trying to solve.

Among those who have gained popularity thanks to the simplicity of its application, we have the five whys technique, a tool that allows us to find the root cause of a particular problem by asking questions.

Although easy to apply this technique, it does require a few steps to follow, taking into account a few tips and also evaluating its drawbacks, which we will see in the following lines. Stay tuned to learn more about this technique!

    What is the five whys technique?

    The five whys technique, also known as the why-why or why scale, is a strategy widely used in problem solving that allows you to find the root cause of a complex problem or that is the product of a succession of causes. Its application is very simple which is why it is so popular and used in the world of problem solving.

    The ideologue of this technique would have been Sakichi Toyoda, a Japanese industrialist and inventor who founded the Toyota company. Toyoda applied this tool to solve problems in automobile manufacturing. It would then be the engineer Taiichi Ohno, also from Toyota, who would give continuity and fame to this technique, popularizing its application.

    The postulate of the technique is simple, so much so that it can be summarized in the following press release sent to the colleagues of these Japanese manufacturers: “observe the production workshop without preconceived ideas and with an empty mind; repeat ‘why’ five times for each subject”.

    Basically, it’s a cause-and-effect analysis tool, which works through questions. With this strategy, you can analyze a problem by asking the “why” question. After we get the answer to that first “why”, we ask ourselves the same question again, and so on, until we find out what caused the problem we solved.

    usually a minimum of five reasons is necessary to find the source of the problem, which is why the technique is named. However, despite what its name says, do not do all five as this does not mean that the tool is not being used correctly, as the question must be asked until it is considered to have was reached at the root of the phenomenon analyzed. , three reasons are enough or seven are enough.

      How to apply the technique to solve problems?

      If this is a fairly loose technique, do an analysis using the five as the proper technique involves taking certain considerations into account.

      Management needs to be involved in the Five Whys process in the business. For the analysis itself, consider which people are the right ones to form a working group with. It is also advisable to turn to someone who can act as a facilitator of the process, in the sense that they are inclined to ask questions on a particular topic.

      It is essential that the process of finding the five be done on a piece of paper or, better yet, a chalkboard. To be able to do it with a computer, but it’s better to do the whole scanning process with something that everyone can physically participate in at the same time. You should write the problem on the board and make sure everyone understands it.

      During the process, it is very important to think about the real causes of the problem and the symptoms or effects they cause, without confusing them. We must not forget that a symptom is still a consequence of something, and that it is for this thing that we must seek a solution. This is why it is essential to be attentive and to follow the logic of the relations of cause and effect.

      We need to make sure that we isolate the causes that caused the failures, problems or inconvenience of the situation we find ourselves in. This is why it is a very good strategy to do the sentences we have asked but backwards, using the expression “and therefore” or “and therefore”. We must try to make the questions as specific as possible.

      The fault should never be blamed on uniquely and exclusively human factors. There may have been human error, carelessness on the part of a worker, or any issue that was in the hands of one or more people, but the whole process should also be evaluated and any human or purely accidental issues. detected must be detected. have. This technique is not used to find those responsible, but to learn from mistakes and prevent them from happening again. It is necessary to foster a climate of trust and sincerity, and accusations do not help to achieve this.

      The question “why? Until the root cause of the problem is determined. In other words, it is if what is found which once resolved or removed prevents the error from being made again, then it has been possible to fully apply the technique. It is strongly recommended that you ask these “why?” From the point of view of the customer rather than that of a worker.

        Examples of application of this technique

        Although the principle of this technique is simple, to better understand it we will present three examples that are sure to give us a more in-depth understanding of how the five reasons strategy works and how it is useful.

        1. Toyota case

        The first example we give is a proposal from Toyota itself. A machine has a malfunction.

        • Why was the machine known? The fuse has blown due to overload.
        • Why was he overloaded? The bearings were not sufficiently lubricated.
        • Why didn’t they have enough lubrication? The lubrication pump was not circulating enough oil.
        • Why was the pump not circulating enough oil? The bomb was clogged with metal shavings.
        • Why was it clogged with metal shavings? Because the pump has no filter.

        So after this analysis we can understand that the dirt in the pump because it did not have a filter caused an overload in the fuse, which caused the machine to fail. In this particular example, we can understand that each cause has its effect, therefore acting on the fifth because the problem must be solved.

          2. Replacement of personnel

          A customer data system seems obsolete:

          • Why is the system giving us outdated data? Because the analyst did not load the updated data from the previous month.
          • Why did the analyst not upload the data the previous month? Because no one taught him how to do it.
          • Why hasn’t anyone taught him how to do it? Because no one knows the procedure.
          • Why does no one know the procedure? Because whoever knew him left and didn’t explain it to the incoming worker.
          • Why was it not explained to the worker entering the procedure? Because it was not documented, nor was the possibility that whoever did not know left without learning the new one.

          This problem, which at first appeared to be just a system crash, is in fact a human problem, in which the parties responsible for updating the data were not aware that it was their task and no one informed him or taught him correctly. There was also no protocol specifying what to do in the event of the departure of the person in charge of updating the data.

            3. Decline in sales

            In one company began to record a decline in sales …

            • Why have sales declined? because traders did not meet their monthly goals.
            • Why Did Marketers Fail To Meet Their Monthly Goals? because they don’t have enough time to focus on their sales.
            • Why don’t they have enough time to focus on their sales? because the daily stagecoaches do not not resolve quickly.
            • Why are daily diligence not resolved quickly? Because the company has not implemented a tool that resolves them quickly and efficiently.

            In this particular case, we see that because the company does not have the tools to quickly solve everyday problems, it is the workers who must succeed in solving them.

            Since many of these problems are unfamiliar to them or are more complex than their knowledge allows, too much time and cognitive resources in its resolution. As a result, we find that they don’t have time to focus on sales and are doing less.

              Advantages of this technique

              We can cite a few benefits and advantages of the five whys technique:

              • It allows you to quickly delve into the nature of the problem through several paths.
              • It is a very simple technique to apply, you just have to ask yourself the right reasons and find out the cause behind each problem.
              • Its use promotes teamwork. Ideally, it should be applied by people who have multiple roles in the business.
              • It can be integrated with other problem-solving tools, such as Ishikawa Analysis or the Six Thinking Hats.

              And as the main advantage that stands out from the rest, we can mention that it acts on the root cause of the problem, preventing it from reoccurring once it is detected, understood and resolved.


              But in spite of having several advantages, the technique of the five because it also has some disadvantages, in particular because some consider it too poor a tool to analyze the root of a problem.

              This view was expressed by Teruyuki Minoura, former general manager of global purchasing at Toyota, believing that this tool does not allow for a deep enough analysis to solve problems in a world as complex as that of engineering.

              In addition to this advice, we have many other reasons:

              • Researchers tend to stop at the symptoms instead of going to a deeper level and seeing the root cause of the whole problem.
              • Inability to go beyond the researcher’s current knowledge. The researcher cannot find the causes because he does not need to have the knowledge to detect them initially.
              • Lack of support to help the researcher give the correct answer to the “why” questions.

              In addition, the results are not reproducible. The proof is the fact that different people using the five technique because for the same problem they may end up finding different causes.

              Tendency to isolate a single root cause and see it in a linear fashion, instead of considering the possibility that there are multiple causes that caused the problem and as a result of the combination of several problems which gives a multifactorial result.

              Bibliographical references

              • Betancourt, DF (April 18, 2018). The 5 Whys: Question-Based Root Cause Analysis. Retrieved October 13, 2021 from Inginy Empresa:
              • Serrat, Olivier (2017). “The five whys technique.” Knowledge solutions. pages 307-310. doi: 10.1007 / 978-981-10-0983-9_32. ISBN 978-981-10-0982-2.
              • Fantin, Ivan (2014). Applied problem solving. Method, applications, root causes, countermeasures, Poka-Yoke and A3. ISBN 978-1499122282.
              • Ohno, Taiichi (1988). Toyota production system: beyond large-scale production. Portland, OR: Productivity Press. ISBN 0-915299-14-3.

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