The Five Whys: Understanding the Root Cause of a Problem

Is your company using Six Sigma to improve efficiency, eliminate waste, and minimize variation? Six Sigma has been a proven success for many businesses around the world dealing with similar problems. But where do these issues come from? How do they arise? And most importantly why?

Six Sigma DMAIC teaches you to Define, Measure, Analyze, Improve and Control problems. But it is the Analyze stage that interests us here. The 5 Whys of Root Cause Analysis (RCA) are essential questions that you need to ask. Unlike other devices, they don’t require testing hypotheses, data segmentation, regression, or other similarly complex statistical tools. The 5 Whys provide all the skills you need in one easy to use toolkit to help determine where problems come from, why they arise.

Root Cause Analysis: How to use the Five Whys

To make the most of what the Five Whys can offer, they need to be completed to the letter. Here is a simple breakdown to help you understand how to use the Five Whys to their full effect.

  • Write down the problem. Be specific. This will help you discern exactly what the problem is. You can then help your team focus on solving it.
  • Why is the problem occurring? Look at where it occurs and try to identify the cause. If it’s a production problem, look closely at the flow.
  • If you still can’t identify the root cause, ask why that is.
  • Return to step 3 until you can agree on what the root cause of the problem is. Scrutinizing these questions in detail will allow you to determine the root cause quickly.

Examples of the 5 Whys

There are no universal maxims that determine what the 5 Whys should be. Between you and us, it’s not always necessary to use all five. It depends entirely on your situation: on what the problem is. But here are some useful examples for you to use as inspiration.

  1. Why are your customers receiving faulty products?
    • Because your manufacturing team made the products using a different specification to the one that both the sales clerk and customer agreed on.
  2. Why does manufacturing keep making products per a different specification?
    • Because the salesclerk accelerates production on the shop floor by calling directly. Specifications may have been miscommunicated to cause this to happen.
  3. Why does the salesclerk contact manufacturing directly to begin production as opposed to following company procedure?
    • Because the sales director’s approval is required before production can begin. This slows down manufacturing or even stops it completely.
  4. Why does the paperwork contain a sanction for the sales manager?
    • Because the sales manager requires frequent updates to be discussed with the CEO.

Here’s another example of how the 5 Whys can be used (in an altogether different situation!).

  1. Q – Why won’t your car start? A – There’s no gas.
  2. Q – Why is there no gas? A – You didn’t buy any.
  3. Q – Why didn’t you buy any? A – You didn’t have any cash at the time.
  4. Q – Why didn’t you have the cash to buy gas? A – You lost your wallet.
  5. Q – Why did you lose your wallet? A – There’s a hole in your coat pocket.

Remember, it’s up to you to use the 5 Whys to your advantage. Don’t let problems fester when they can be easily resolved!


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