5 WHYS: How to quickly and effectively find the root cause of a problem

How many times have you been part of the following situation? You’re trying to figure out the cause of some problem in your department or on your team, and you keep coming up with different possible solutions, but none of them are working? If this has happened to you, don’t worry; most people have had to go through it at one point or another. And while there are several ways to find the root cause of a problem, it can be tricky to figure out which method will work best for your situation.

Asking “Why?”

A simple Why? question may drive you crazy, but it teaches you an invaluable lesson about Six Sigma. Five Whys is one technique in the DMAIC process (define, measure, analyze, improve, and control). It is a very practical Six Sigma tool that does not require a lengthy and difficult data segmentation process, complex hypothesis testing, statistical modeling, etc.

A process for peeling away symptoms in order to get to the root cause of a problem is to keep asking, Why? and to keep questioning.

Benefits of the 5 Whys

1. To identify the underlying cause of a problem.
2. Figure out the relationship between the different underlying causes of a problem.
3. One of the easiest tools to work with and complete without statistical analysis.

When Is 5 Whys Most Useful?

Human factors and interactions play a role in solving problems. Can be used within or without a Six Sigma project in everyday business life.

How to Complete the 5 Whys

Step 1. You can formalize and describe a problem by writing it down. As a result, a team is able to focus on the same problem more effectively.

Step 2. Write down the reason why the problem occurs below the problem.

Step 3.  Ask Why again if your answer does not identify the root cause of the problem you listed in Step 1.

Step 4. Continually loop back to step 3 until the team agrees on the root cause. This may take fewer or more than five Whys.

Identify Problem

You have just been alerted about an issue in your system, but now you need to know what caused it. The 5 WHYs Framework is a technique that can help you identify the root cause by asking why five times. The first thing you do is write down what happened. Then ask yourself why it happened. Write down your answer, then ask why that happened. Keep going until you get to the root cause of your issue (which may not be obvious).

Ask Why? 5 times

1. Why did you do that?
2. Why are you feeling that way? 2. What is going on in your life right now?
3. Why do you think it’s happening now?
4. What is really bothering you about this situation?
5. What are some other problems that could be related to this one or making it worse?

Fix The Problem

When solving problems, try the 5 WHYs Framework. This will help you focus on understanding what is causing the problem by asking why five times. For example, if your phone broke, you might ask questions like: Why did my phone break? Why did it fall? Why did I drop it? Why was I carrying it that way? Why was I carrying something else at the same time? By asking these questions, you can better understand why your phone broke in order to prevent this from happening again.

Take Action Now

The 5 Whys Framework is based on the idea that we often don’t understand why we do what we do. We might know what we’re doing, but not why. The 5 Whys Framework is designed to help you get at the root cause of any problem by asking why five times.

Start with Why?

Ask Why did I take this action? This will prompt you to think about your motivation behind taking an action.

Review & Improve Processes

Reviewing your processes will help you identify opportunities for improvement. Plus, it’s an important step in finding out what might be contributing to any problems you are experiencing. The 5 Whys Framework is a helpful way to do this.

5 Whys Examples

1. Why are customers being shipped bad products?

Because manufacturing built the products to a specification that is different from what the customer and the sales person agreed to.

2. Why did manufacturing build the products to a different specification than that of sales?

Because the sales person expedites work on the shop floor by calling the head of manufacturing directly to begin work. An error happened when the specifications were being communicated or written down.

3. Why does the sales person call the head of manufacturing directly to start work instead of following the procedure established in the company?

Because the “start work” form requires the sales director’s approval before work can begin and slows the manufacturing process (or stops it when the director is out of the office).

4. Why does the form contain an approval for the sales director?

Because the sales director needs to be continually updated on sales for discussions with the CEO.

All we needed to find out was that one non-value-added signature authority is exacerbating the breakdown of the process.

For something slightly more amusing, take a look at an edited version of a passage from the Six Sigma Dictionary, 5 Whys from Marc R.

Example 2 

Problem Statement: On your way home from work, your car has a stop in the middle of the street.

1. why did your car break down?

So it ran out of fuel

2. Why did it run out of fuel?

it seems like I forgot to buy fuel on my way to work.

3. Why didn’t you put fuel in your tank this morning?

Because I was flat broke.

4. Why didn’t you have any cash?

well, last night I had a poker game and I lost it all.

5. Why did you lose your money in the poker game last night?

Because I’m terrible at lying when I don’t have anything.

Clearly, in both examples, the final Why leads to a statement (root cause) that the team can act upon. If one could develop a way to keep the sales director informed about recent sales, or teach someone how to “bluff” their way through a hand, it would be much quicker than attempting to directly solve the stated problems.

Take-away Quotation

Unless you ask the right questions, you won’t get the right answers. When asked in the right way, a question often points to its own answer. Only an inquiring mind can solve problems.”