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5 Whys Analysis - Simple but Effective

5 Whys is a simple and effective tool used to get to the root cause of a problem.

Subjective in its approach, it relies on the group analysing the problem, to come to their agreed conclusions as to what the root causes are to the problem at hand. It also relies on technical experts being present to drill down through the symptoms to get to the root cause.

The 5 Whys are set around asking ‘why’ to a problem, getting the answer and then asking why again and again, until you come up with the real root cause of a problem.

Think of it as being a child again, where you used to annoy your parents by asking a question, them giving you an answer and you proceed to repeatedly ask why to every consecutive answer. That is the 5 Why problem analysis tool!

The 5 Whys is not necessarily about asking questions five times – you ask ‘why’ as many times as you need to, in order to get to the real cause of a problem.


In the simple example below, just by repeatedly asking why, enables you to get to the root cause. It is worth noting here, that most root causes are due to a lack of a robust system or process, or that there is no process in the first place and the example below shows that there is no real system in place to replace the batteries.

Once the root cause has been highlighted, the team or individual can then go about rectifying the problem and remove it for good.

5 whys example

Real Life Example

In a large company I worked at as a Business Improvement Leader, there was an instance where lots of scrap was reported from the previous day’s production on one machine.

The operator pushed the emergency stop button by mistake during a run. When I asked why, the answer I got from a senior /manager was: “Operator error.” I then asked why was it an operator error? “Because it happens now and again,” he said with a frosty reply.

I then said that “I do not buy that answer. How can we error proof the process so the operator doesn’t get blamed and also so we don’t make the same mistake again?” “You can’t, its life!” was the reply…….

I asked again, “why did he hit the emergency stop?”

Another manager was getting embarrassed and then said, “lets have a look on shop floor.”

We went to the source and found that the start and stop buttons on the machine in question, were both dirty to the point that their distinguishing colours of red for stop and green for go, were not displayed – they were both black. More so, the buttons were so close together that it was so easy for the operators to push the wrong button by mistake.

In essence, after a long debate and pain, we got to a more legitimate reason:

There was excessive scrap on the process line


The operator pushed the stop button instead of the start button by mistake, during the run.


Because the buttons on the control panel are unclear and dirty and the stop button is right next to the start button, making it easy to hit the wrong button.

ANSWER: Clean the area and control panels – Set the new 5S Standard and move the emergency stop button to the side of the machine, away from the start button.

By asking why, we went from the problem being an operator issue to the fact that there was no 5S housekeeping. Two actions resulted:

1. Clean and organise the area, setting acceptable standards for the machine, also keeping the buttons clean and clear from dirt.

2. Move the stop button to the side of the machine and away from the start button to prevent pushing the wrong button by mistake.

How to use the tool

The 5 Why tool can be used as simply as the above examples demonstrates.

1. When you have identified a problem, focus on the problem statement – What is going wrong, when did it happen, and then work backwards, asking why every time. Focus on getting to the root cause, which is normally a process issue.

2. Inexperienced facilitators and groups often find that their answers or route causes often point towards generic statements and reasons that are out of their control, like ‘Operator error’, ‘ not enough time,’ ‘not enough labour’ etc. Nine times out of ten, the route cause is a process issue, so focus on finding a rout cause that embodies a problem with a process, or even that a process doesn’t exist in the first place.

3. Remember, when conducting the 5 Why exercise, keep in mind that a bad process will beat good people every time, so focus on the process issues, not people. It sometimes helps to ask ‘Why does this process fail?’ after every question, to keep on track.

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