5Whys Analysis is one of the simple and best tools to identify the root causes of a problem.In this article, we will explore the detailed structure of 5 Whys Analysis, Pre-requisites, Correct usages and its Limitations.
What is the purpose of 5 Whys Analysis?
Any problems can be addressed with corrections and corrective actions. While corrections deal with mainly on the affected parts, the corrective action focuses on the root cause of the problem. The purpose of asking 5 Whys is to understand the cause of a problem. Causes are required to prevent the occurrences or failures.
For example, a TV manufacturer’s packing team finds a visible scratch on a TV panel in its automatic packing line. Immediately, the scratch is removed by using appropriate surface finishing processes. The actions taken to remove the scratch is called as correction. But the issues not resolved yet. The reasons for the scratches yet to be identified and to be removed from the process. This will ensure that the same mistake will not repeat. Now, the TV manufacturer’s operation team finds that the scratch happened due to some vibration issues occurred in one of its material handling devices in the automated packing line. Necessary actions taken to minimize the vibration in the device. The actions taken against the cause of the issue is called as corrective action. In this case, the cause is excessive vibration of material handling device. The purpose of 5 Whys analysis is to find out the cause of the problems.
What is 5 Whys?
5 Whys Analysis is a simple way to ask ‘Why’ 5 times specific to a problem statement, for identification of root cause. For example,
1. Why the scratch occurred at the TV panel ?
Because, of improper handling by the robotic devices.
2. Why the improper handling occurred?
Because, the robotic arm was not holding the panel properly, due to vibration.
3. Why the vibrations occurred?
Because, the arm bolts were not tightened enough.
4. Why the bolts were not tightened enough?
Because the operators were not aware of the tightening torque.
5. Why the operators were not aware?
Because, maintenance check list not mentioned the required tightening torque of the bolts
By simply asking 5 whys, in this case we could find that the missing information related to torque requirement in the maintenance checklist has caused the scratches in the TV panel. Hence the corrective action would be revising the maintenance checklist by including torque tightening limits.
How to use 5 Whys?
There are chances to use the 5 Whys incorrectly. The answers to the preceding questions decide the questions for the succeeding one. Hence, a small misunderstanding, misinterpretation and lack of process knowledge would lead to hide the real causes from our eyes. Following example is one form of incorrect way. For simplification, the example used in the above paragraphs are considered here;
|Sl.||Correct Way of asking 5 Whys||Incorrect Way of asking 5 Whys|
|1.||Why the scratch occurred at the TV panel ? Because, of improper handling by the robotic devices.||Why the scratch occurred at the TV panel ? a. Because, of improper handling by the robotic devices.|
|2.||Why the improper handling occurred? a. Because, the robotic arm was not holding the panel properly, due to vibration.||Why the improper handling occurred? a. Because, the robotic arm was not maintained properly.|
|3.||Why the vibrations occurred? a. Because, the arm bolts were not tightened enough.||Why the robotic arm not maintained properly? a. Because, the maintenance operators were not done their work effectively.|
|4.||Why the bolts were not tightened enough? a. Because the operators were not aware of the tightening torque.||Why the operators were not done their work effectively? a. Because of lack of supervision|
|5.||Why the operators were not aware? Because, maintenance check list not mentioned the required tightening torque of the bolts||Why lack of supervision and training observed?? Because, they have not adequately trained.|
The table shows that how an analysis changes when the focus shifts from vibration to operators work. It indicates, lack of knowledge and information on the subject can lead us to execute an incorrect 5 Why Analysis. Therefore, while doing the analysis one must take proper care in identifying the questions and to ensure that all the concerned people relevant to the issues are present during the analysis, including the subject matter experts.
Limitations of 5 Whys Analysis
The analysis requires more practical knowledge and experience on the subject. It mainly depends on the person’s skill.
- There is no assurance that, within 5 Whys one could obtain the root cause of the issue. (Sometimes, it requires less than 5 Whys or some time it would be more)
- In case of more than one root cause, this 5 Whys Analysis does not always address those causes. It is up to the person who chooses based on his knowledge.
- The root causes not derived through statistical analysis hence there would be always some subjectivity attached to it.