Avoiding this is a very important job of all people who work in a company, primarily a lean expert, or someone who works on the quality team. There are many ways in which the quality team can approach the problem, and the 5 why technique is one of them. It is designed to help get to the real root cause of a problem, so the cause can be addressed through a short term or long term corrective action. The corrective action, then, can be tracked for its effectiveness.
The 5 why system is one in which the simple question “why?” is asked at 5 different levels of a problem to get to the bottom of the situation. It was first used in the early 1970’s by the Toyota Company, who is often credited with being the pioneer of modern quality.
If used correctly, it can provide a way to help identify the true root cause of the problem by using a feedback system. An added benefit is that it can be used both on an individual basis as well as a part of a group attack. It can, and should, also be integrated into the Kaizen, lean, and Six Sigma methods.
It can also be used in conjunction with other tools, such as root cause analysis software and fishbone diagrams to help aid in the discovery of the true root cause and identifying the cause and effect associated with it. While some other root cause analysis tools are complex and require experts to run them, even a two year old knows how to ask the question “why”, so the much more simplified approach is easy to adopt to the level of each individual worker.
Of course, it may seem like the five why method is too good to be true: a simple, effective way to approach complex technical issues that anyone can apply? This is the exact argument that most “five why” critics have used against the system: it is not as effective as thought.
The biggest argument is that, while it is purported to get to the foundation of the problem, in reality, most people stop at the surface level symptomatic issues that appear to be plaguing them on a daily basis. By asking the question “why?”, most will simply come up with another symptom instead of working their way back to the root cause. They will then fix the additional symptom, proclaiming to have found and corrected the root cause, when in fact the problem they were trying to solve never actually is fixed.
Another pitfall that the critics of this system claim detracts from its effectiveness is the tendency for personnel to stop at their level of knowledge or comfort, instead of digging deeper and thoroughly investigating the limits of their technical knowledge. It is too easy for the “five why” method to reward and promote the “quick fix” answer of simply satisfying the question “why”, instead of more thoroughly finding a technical answer.
Lastly, while simplicity is one of the merits of the system, it is also purported to be one of the downfalls. Because anybody can conduct the five why method, they actually do, and do not seek professional assistance in determining whether the “why” they submit is a true, actual “why” and not a surface level quick fix.
Of course, there can be more than one “why” to every reason, as demonstrated by Figure (1). The seal could leak because of improper installation of the seal, or possibly an inadequate seal design. Each one of those has their own “why” branches, which address the more subsurface issue causing the “why” before it.
As stated earlier, anyone can use this method. However, care and consideration should be taken to at least fully train the personnel who will be in charge of leading the five why inquisition, as it is very easy to scratch the surface of the challenge and never actually dig to the subsurface root causes.
The 5 why technique is a great tool when used in conjunction with other tools as an aide in finding the root cause of a problem. Like any other tool, it should be wielded by someone who understands how to thoroughly investigate problems and conduct a solid root cause analysis.