The 5 Whys – and a How

Mr. Sakichi Toyoda may not be a household name, but he made significant contributions to modern business. He created a textile machinery company that has now given way to one of the most influential automobile manufacturers on the market, Toyota Motor Corporation. A true innovator in his time, he is noted as being the father of the Japanese industrial revolution. He is also credited with the creation of the 5 Whys Technique, which Toyota still claims is “the basis of Toyota’s scientific approach.”

Why and how?
This technique asks five questions, or whys, to find a cause/effect relationship with the existing problem, and then determines a root cause for it. Although this technique is very useful and has proven successful, I wonder if we should not be asking “how” as well.

When asking why, sometimes the right question is difficult to determine. An initial wrong why could lead to a long line of misleading and fruitless questions. Imagine asking how as well or in place of the why.

Why did he/she hurt their arm on the conveyor belt?”

How did he/she hurt their arm on the conveyor?”

These questions can be answered completely differently. How should enable us to go down a different path, one that will not necessarily put all the blame on an individual or group.

  • How enables us to go deeper into trying to understand the reason for the injury/incident. In other words, maybe the best approach would be to ask both how and why.
  • Dig deeper into the problem and search out the reason for the incident. In some circumstances, there might not be a single root cause to the problem that occurred.
  • Asking both how and why for each step of the process might reveal that there are multiple causes to the condition at hand which in turn means there are different steps that need to be taken to correct the cause.

Why stop at 5?
Something else to consider: what if there are more than five questions to be asked? One of the fallacies with the 5 Whys is that people often stop after the fifth question asked. 5, 10, or even 50 or more questions might be merited.

Many seasoned 5 Whys advocates have made the transition to asking more than five questions. This technique is now called causal analysis. But, they still use the 5 Why model. How are they using it? They simply move it to the end of the analysis. The causal analysis identifies many contributing factors that might reside in different areas not directly attributed to the loss or incident. Once these numerous causes are discovered THEN the 5 Why questions can be asked, and in turn, the process can be more effective.