5 Whys: Finding the Root Cause of Problems

Peter Robustelli DMAIC Tools, Knowledge

What is 5 Whys analysis?

Five Whys analysis is a simple but highly effective means of getting to the root cause of a problem. The starting point is to define the problem clearly – for example, the drinks being dispensed by the vending machine aren’t as hot as they should be, or Team B aren’t hitting the targets set – then to ask “Why?” Once you answer the first “Why?” you pose that answer as a statement and again ask “Why?” You then do that a further three times.

Here is a theoretical example of how 5 Why analysis could work in practice:

Problem – Car isn’t starting

  1. Why? – The battery has died 
  2. Why? – The alternator has stopped functioning
  3. Why? – The alternator belt is broken 
  4. Why? – The alternator belt has exceeded its useful service life and wasn’t replaced 
  5. Why? – The vehicle wasn’t maintained as per the recommended service schedule (Root Cause)

This allows you to drill down to the core problem – the root cause – at which point a course of corrective action should be apparent. The intention is to identify what is needed to prevent the problem from recurring, rather than just applying a quick fix.

The 5 Whys root cause analysis template is highly effective and so has been adopted in other methodologies, too, including lean manufacturing, Kaizen and Six Sigma.

Where did the 5 Whys analysis originate?

The 5 Whys technique was developed in the 1930s by Sakichi Toyoda, founder of Toyota Industries, and it’s still in use there today. The purpose is to identify the root cause of the problem when a process results in an unsatisfactory outcome. 

Often the root cause can be unexpected – what looks like a machine error may in fact be a human error, or vice versa – but the 5 Whys analysis template has been shown to be sufficiently curious to get to the core issue. It’s also important to bear in mind that 5 Whys analysis isn’t about apportioning blame; it’s about understanding the root cause of a problem and then putting in place countermeasures to prevent it from happening again.

A key component of 5 Whys analysis is that it is based on what is actually happening on the shop floor, rather than what should be happening – Toyota call this their “go and see” philosophy. Focusing on the reality rather than the ideal allows the real problem to be analyzed and reveals appropriate countermeasures.

Of course, if what is actually happening is different to what is supposed to be happening, once the immediate problem has been dealt with, it might be appropriate to ask why there is a discrepancy between written procedures and actual practice.

When should you use 5 Whys analysis?

There are times when 5 Whys analysis is the ideal system to use and times when it is perhaps less useful. It is arguably most effective when you are dealing with a fairly straightforward issue, rather than something complex or multi-faceted, due to its hyper-focused nature and the way it is designed to drill down rather than encourage broader, more investigative approach. That makes 5 Whys analysis the ideal choice when it comes to resolving relatively uncomplicated problems.

It can also be used to good effect in the case of quality improvement, either when issues arise with regard to a shortfall in the level of quality expected, or when an initiative to improve quality is to be implemented.

5 Whys Analysis Steps

When it comes to putting 5 Whys analysis into action there are, perhaps appropriately, five distinct steps involved in the process.

Step 1: Assemble and Form a Problem-Solving Team of People Affected by the Issue

The effectiveness of 5 Whys analysis relies upon the knowledge of the team. Make sure those involved in drilling down to the core problem have the knowledge, skills and information specific to that particular issue. Also, be sure to appoint a facilitator – or 5 Whys Master, if you prefer – so that the discussion and analysis retains its focus and doesn’t go off at a tangent.

While each team member should be knowledgeable with regard to the issue(s) being analyzed, it can be beneficial to pull together people from different departments. That’s because the combined informed wisdom of people with different viewpoints is stronger than that of people who may all be coming at an issue from the same angle. Diversity can give strength and help ensure a well thought-through response to the problem.

Step 2: Define and Identify the Problem

The starting point of any 5 Whys analysis is the problem. That sounds obvious, but without a clear understanding of the issue in scope, it’s all too easy to drill down on the wrong aspect of a problem, or even to focus attention on the wrong problem all together.

Spend some time discussing the problem and make sure everyone fully understands the issue. Remember Toyota’s “go and see” philosophy; make sure you know what is actually happening on the shop floor, and avoid making any assumptions based on what should be happening.

It’s a good idea to write down the ultimate definition of the problem to be analyzed, so that you can be confident everyone is laser-focused on the specific issue under investigation. Time spent here will pay off handsomely down the road.

Step 3: Ask “Why?” 5 Times

Once the issue has been understood and defined, the 5 Whys Master should pose the first “Why?” Following discussion, the answer to that “Why?” can be defined in the same way the original problem was, and then the 5 Whys Master should ask “Why?” again.

Asking “Why?” might sound simple but the value here is in first defining the problem accurately, and second, arriving at the most accurate answer to the question – “Why?” – framed in relation to that problem. Remember, this is based in fact not in theory so careful, informed analysis will reveal both the root cause and the optimum countermeasure(s) to be taken.

It’s important that the team stays open-minded here and avoids jumping to conclusions, even if one or more members is sure they know the answer early on. They may well be right – but this kind of analysis can surface unexpected root causes. Stay with it and stay open-minded.

Incidentally, while five whys are considered the optimum number to ask in most cases, if you get to the answer after three – or if it takes seven – that is less important than getting to the true root cause. Also, be prepared for there to be more than one root cause; if there is genuinely more than one answer, take them all into account. Don’t just dismiss some in search of the single right answer.

Step 4: Take Action and Implement Solutions

Once the root cause has been identified, the team should define the corrective action(s) to be taken in order to ensure that the problem never occurs again. Possible countermeasures should be discussed, and the optimum approach identified.

It’s a good idea to make someone accountable for applying the countermeasures, so that you can be confident the 5 Whys analysis process is implemented and provokes change. The last thing you want is for all that hard work to be wasted. 

Step 5: Monitor and Review

For a period of time, the effectiveness of the countermeasures that were put in place should be monitored. After a set period, the team should get back together to appraise the results. If the desired outcome has been achieved, it means the countermeasures have worked and can therefore be maintained. If, however, success has been partial or, worse, non-existent, then the process needs to start again, taking the previous failed analysis into account.

It could be that the initial problem wasn’t fully understood or accurately defined, meaning the countermeasure was ineffective as it sought to address something other than the actual problem. Always bear in mind Toyota’s “go and see” philosophy; don’t be afraid to get down on the shop floor and talk to people. Also, don’t just talk to the managers or supervisors – talk to the people who are actually doing the job or playing casino games: they’re the ones who know what’s happening and they may well have some great insights to share.

Once a satisfactory outcome has been achieved, the process should be documented and shared on the website with casino reviews.

Identifying and addressing the root cause of a problem is the best way of fixing it and ensuring it doesn’t occur again. The 5 Whys analysis is central to this, and a tool that we regularly utilize when assisting our clients. Please don’t hesitate to contact the team, or browse our Knowledge Base for more insights on root cause analysis and business improvement. 


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