Root Cause Analysis: The 5 Whys Technique

Have you ever found yourself proffering the wrong solution to a problem? You can avoid this by applying the 5 Whys technique - a technique for identifying the exact root cause of a problem to determine the appropriate solution. Made popular in the 70s by the Toyota Production System, the 5 whys is a flexible problem solving technique. I find it intriguing. Partly because it's so simple and partly because it requires skilled facilitation to be effective, straightforward as it is. It is however, best used for solving human interaction problems. Because most problems have a human element to them, the idea is to trace "technical problems" back to their human causes, where possible.

This technique is similar to how children ask questions. As soon as you give a response, they immediately want to know why the answer is the answer. The 5 Whys technique is one that advocates asking why as many times as you need to until you get to the root cause of the problem. The idea is to stop asking why when you have arrived at a probable root cause of the problem, which may come before or after the 5th why. The technique requires that you remain objective all through. It may be combined with the Ishikawa diagram, resulting in an even more powerful problem solving technique.


In order to apply this technique to your project, follow these steps:

  1. Write the problem on the centre of a flip chart
  2. Ask the participant(s): Why do you think the problem occurred?
  3. Capture idea 1
  4. Ask the participant(s): Why do you think Idea 1 occurred?
  5. Capture idea 2
  6. Ask the participant(s): Why do you think Idea 2 occurred?…on and on it goes until you get to the root cause.

Here's an illustration of the 5 Whys technique:

Problem: Our company lost sales to the tune of $10M in 2011. 
    Why? Our demand forecasts were constantly wrong.
            Why? We did not get any input from the field
                    Why? The field agents did not have access to systems
                            Why? The IT department did not allocate any systems to them
                                  Why? Management did not think it was a priority (root cause)

Sometimes, getting participants to agree on a single idea is not always possible. Where more than one idea is proposed as the cause of the problem, explore each idea (or path) until you arrive at its root cause. it's best to complete one path before moving on to the next; you may find that exploring other paths may not provide additional insights. With complex problems, there's likely to be more than one single cause - this is where combining the technique with the Ishikawa Diagram comes in handy.

The principle behind it is this: instead of treating symptoms, why not go for the root cause? Symptoms often mask the cause of problems and the 5 Whys technique is an effective way of identifying that root cause.


  • 5 Whys is best used during brainstorming sessions - the idea is to get everyone to contribute ideas that will lead to identifying the root cause of the problem
  • Sometimes, exploring a particular path may get you nowhere. There's no point exploring a path that will not lead to any useful learning, so feel free to stop and move onto the next path
  • Invite only participants that are knowledgeable about the problem domain; they will be able to generate insightful responses that will aid arriving at the root cause. This will also ensure that everyone is in agreement about what the root cause of the problem is. At the least, those affected by the problem, as well as those who discovered it should be present.
  • As soon as the root cause is identified, recommendations that tackle the problem as quickly as possible should be drawn up. In coming up with recommendations, focus should be placed on the root cause as well as the whole chain of events that led up to the problem. Improvements should be communicated to all stakeholders so that the benefits of the exercise are clearly visible.
  • Most problems aren't linear - there are often more than one possible cause of a problem. Try as much as possible to see where one path leads before switching to another. Where stakeholders do not agree on the probable cause of the problem, use voting to arrive at a consensus.
  • Focus should always be on what caused the problem and not what to do to fix the problem. For example, one might attribute the reason for employee lateness to be a lack of lateness penalty. While having a penalty for lateness may reduce lateness, it may not necessarily be the reason why employees come in late. They may be coming in late because they are over-worked, due to personal responsibilities, poor time management or even a lack of motivation. 

Beyond helping the business analyst understand the root cause of problems, the 5 Whys technique can also be used to understand what your customer is really saying. Read this interesting approach on the Green Hornet Connect Site.

Useful Links

Clear and insightful Explanation on the 5 Whys Technique 
lready using the 5 Whys? Here's how you can do better