The 5 Whys in Root Cause Analysis

5 whys image

The “5 Whys” is a question-asking technique used to determine the root cause of a problem by repeatedly asking the question “why” until the root cause has been identified.

The question isn’t asked just 5 times, if you get the root cause after 4 whys you stop, if after 5 whys you don’t have the answer you continue with 6,7,8, or however many whys are needed.

Depending on the complexity of the problem or the process being looked at, you may decide to use a fish-bone diagram or tables/matrix to display the analysis.

This may give you a better view of the cause and effect relationships of the possible root causes behind a problem or process.

You may also find that you only need to ask the questions to get to the root cause.  Each scenario is different and it is up to you to decide how you should proceed.


5 Whys Example

Let’s use a customer complaint as an example of where you could use the 5 whys technique.

Several customers have complained that when they receive deliveries, the items are different to what they have ordered.

Upon first review, the Sales Manager can see that an order has been generated for items X, but production have made item Y.  Production have been making products of a different specification to the order.  Is that what caused the problem?  Do you go to the Production Manager and complain that the production staff are not completing orders properly?

In the real world, this is probably what would happen.  It is very easy to point the finger at somebody else and say they are not doing their job, but let’s use the 5 whys here.

#1 Why are customers complaining that they are not getting what they ordered?

Because production have made and dispatched products of a different specification to that which was ordered by the customer on their order sheet.

#2 Why did production make products to a different spec than the order sheet?

Their was a miscommunication between the Sales Rep and Production Planner.  When the Sales Rep rang in with the order part of the order details were either left out by the Sales Rep or not noted by the Production Planner.  The Production Planner did not see the actual order sheet until after the order was dispatched.

#3 Why was the order taken by phone and not from the order sheet, per procedure?

It can take up to 6 days to have an order sheet processed and then production would begin.  The Sales Rep did not want to delay the production of the order by almost a week.

#4 Why does it take up to 6 days to have an order sheet processed?

The Sales Rep spends most of the week travelling to customers and only one day per week in the office.  When in the office he passes over all order sheets for that week (but he would have already rang in the orders because of the urgency).


For the sake of demonstration, we will stop here at 4 whys and say that the paper-based order to production process may be the root cause here.

If this company used an electronic version (either online, or emailing an order form) this would ensure that the Production Planner sees the full order from the customer prior to production beginning.  The Sales Rep can have the orders sent to the office immediately and doesn’t have to wait up to 6 days before he is in the office again.

In reality you might dig deeper, or use a table or fish-bone diagram and find that the production lead time is too long and that is why there is an urgency with the orders.

You may decide that the customers’ planning systems are inadequate because they are not allowing sufficient order-production lead time, resulting in the tight timelines.


The root cause here is not a person, but a process.

You may find that to be the case a lot of the time, that a process has failed and not a person.

Several writers have said “people don’t fail, processed do”, “people don’t fail, systems fail” and so on.

Other writers say that processes don’t fail, people fail processes.

Whatever school of thought you decide to side with is up to you, we could get into an all day debate on this issue

The important thing to do when looking at a problem is to find the root cause and tackle that, rather than treating the symptoms.  This is a link to an earlier post on root causes and symptoms.


Final Word Of Warning!!

magic wandBefore ending this post, there is one think I would advise if you are planning on using 5 Whys.

From personal experience, I recommend briefly explaining the technique you are about to use – it can be very frustrating to be repeatedly asked  “why” if you aren’t expecting it!

Think about how annoying a 4 year old can be asking “why” all the time.

The difference here is that you won’t accept “That’s the why”, “It just is” for “Fairies do it” as acceptable answers.



[grwebform url=”” css=”on”/]
Click Here to Leave a Comment Below 1 comments

Get every new post delivered to your Inbox

Join other followers:

%d bloggers like this: