Student

5 Whys A kid keeping asking “why” might drive a majority of people crazy. However, Sakichi Toyota, the father of the Japanese industrial revolution, is intrigued by this kid and come up with the concept of “5 Whys”, which is a simple but extremely powerful quality improvement tool to identify the root cause for a problem. Later, this concept, widely and successfully applied within Toyoto Motor Co., Ltd, became well-known as a part of “Toyota Production System”, as well as “Lean Manufacturing”. Essential to this approach is when encountered with a problem, repeating asking “why” 5 times until the fundamental reason becomes clear. Certainly, 5 times is just an arbitrary number that could lead you to the root cause most of the time. It is not a fixed number. More or fewer repetitions are also acceptable if the critical issue of the problem could be found. The concept of “5 Whys” is most commonly used in manufacturing field, but the idea could also be applied to the other fields, such as business and daily life. As an example of how it could be applied in retailing, customer service receives a complaint about a refrigerator one day. At this time, instead of just refunding or replacing, some questions should be asked to prevent recurring of the same situation. The first question could be why the buyer is not satisfied. After contacting the customer, a dent in appearance is found as the reason. Another question in dealing with the complaint is why we need to continue asking “why”. It is because complaints received about appearance are higher than the expected defective percentage. Then the third problem, why there is a dent, pop up. By investigation, the dent is caused by a packing machine. However, the refrigerator sold in other countries did not receive similar complaint, which triggers the next “why”. A notch is found on one of the packing machine in the corporative local transportation company. Then the last question could be why the transportation company is not notified with this problem before. The answer is the iron sheets of our refrigerators are thinner than the products of other companies. With the analyzing method, “5 Whys”, the root cause has been found and the problem could be solved. Following five basic steps, “5 Whys” could be easily developed. The first step is gathering a team to come up with a problem statement. If necessary, additional team member could be involved after the first step. Second, starting brainstorm and asking the team first “why”. Record the plausible reason in a whiteboard. Third, keeping asking “whys” for each plausible reason and their successive statement until the root cause is found and no more useful information is generated. If possible, put the parent answer and their child statement together. After the completion of discussion, the fourth step is to identify the most likely reason for the problem from all the candidates. The last step is to develop corresponding plan to correct the root cause and prevent the same mistakes happening again. Benefits of “5 Whys” include Simplicity, Effectiveness and Flexibility. This approach is easy to teach and implement. It is a technique based on teamwork. Other than experience and knowledge, no additional cost is needed for data mining techniques and software. “5 Whys” performs effective to structure people’s thinking process. It could accurately separate symptoms and root cause of a problem. In addition, “5 Whys” could be flexibly and effectively integrated with other quality improvement methods. The technique, however, can have drawbacks. Since it is a team-focus technique instead of a data-driven tool, the results are not repeatable and might easily biased if the team lacks related experience. Another drawback is in reality, a problem might be caused by multiple reasons. Consequently, “5 Whys” is not a good tool to deal with those problems for a team with limited experience.