5 Whys - A Simple Tool for Root Cause Analysis

It turns out that as kids we knew better: ask Why? 5 or more times to discover the reasons behind the need to go to bed earlier or to understand why dad needs to leave the house in the morning every single work day. But what have we learned about asking Why? over and over again since our childhood, and how can we use this knowledge as process improvement practitioners? This approach is very intuitive indeed, but perhaps not so much utilized as an effective, easy-to-understand, hassle-free tool for quickly identifying the root cause of a problem. Formally described as the 5 Whys technique, it was made popular in the 70's by Toyota and its Toyota Production System (TPS). By asking Why? 5 or more times, one can dig deeper into the cause(s) that are actually creating the symptom. Just as we did by often asking our parents Why? a dozen times in a role - on any subject matter, we can now apply this simple tool in our workplace. Let us use a simple example to understand the power behind such a modest concept. In this post, we also address the next steps to be taken after the root cause of a problem has been found.

Issue: loss of a customer in a busy downtown coffee shop.

Why did we lose the customer?

Because there was a very long line around rush hour.

Why did we have a long line around rush hour?

Because one of our new baristas could not make coffee as fast as requested by our standard.

Why couldn't this barista perform as fast as requested by the standard?

During training, our main coffee maker was not working properly. The barista never really learned how to effectively make coffee as per our standard.

Why wasn't this coffee maker working properly?

The technician responsible for fixing it did not show up to fix it.

Why didn't this technician show up to fix it?

Because we haven't paid the last bill from the service provider.

The points of this fun exercise are twofold: 1) often we think we know the root cause of a problem but not very often we study what really happened. In this example, the first thing that comes to mind is that it was rush hour, and the demand in the coffee shop was higher than usual - an easy to accept excuse to explain the loss of a customer. 2) the root cause of a problem can be sometimes something completely different from the first one we tend to elect as the root cause. As human beings we naturally tend to jump to conclusions but as process improvement experts we should always investigate the issue a bit further, and always dig deeper into the many other possible causes of problem, even when they seem to be so convincing at a first glance. 

What comes next? An action plan to address the root cause(s). This action plan must at least identify a person accountable for the action, a deadline to complete the action, and a follow-up report on it: this will provide your organization with the lessons learned for the future.

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