Root Cause Analysis – Asking Why?

I have two children, ages six and five (Happy Birthday to the boy today, BTW), and they went through a phase where they would ask “why?” for just about everything imaginable. They either grew out of this phase or grew tired of my circular reasoning which resulted in conversations such as:

“Papa, why [whatever]?”

“I don’t know.”

“Why?”

“Because I don’t know everything.”

“Why?”

“Because no one person can know everything.”

“Why?”

“I don’t know.”

And we would continue that loop a few times until they grew tired of getting the same answers about how I don’t know everything and no one person can know everything. Turns out that my five and six year old were only just showing that they have incredible skills when it comes to Root Cause Analysis (RCA). Asking “why?” is a fundamental part of an RCA as it can help to identify potential root causes.

5 Whys

The ‘5 Whys’ is a technique used in RCA and Six Sigma and one we reviewed yesterday during training. I believe that all too often we find ourselves affixing band-aid solutions to symptoms, especially in IT, as opposed to finding and fixing the root cause. The process is quite simple, you just keep asking “why?” until you get to the root cause. So, you may find something like this scenario:

My dedicated log disk filled up last night. Why?

Because someone tried to load ten million rows all at once instead of batching the load into smaller chunks. Why?

Because the package they use for their ETL process does not include logic to batch a transaction size. Why?

Because they do not understand where the option is, or why it is important. Why?

Because no one has explained it to them. Why?

Okay, fine, I’ll go over there after I finish my coffee if you promise to leave me alone. Why?

Stop it. Leave me alone. Why?

And so on until your head will explode. Typically after asking “why?” for the fifth time you might be at the root cause but asking five times is only a rule of thumb. Sometimes you need to ask more, sometimes you can ask less. The key here is to drill down into discovering a potential root cause. You should not consider this tool to be able to easily identify the root cause each and every time. In fact…

Why 5 Why May Not be Effective

Look, no tool is perfect. And the ‘5 Why’ tool is not all unicorns and rainbows either. As much as I can appreciate the simplicity of the technique the fact remains that it has a couple of glaring issues. First, it is not repeatable. That means that two different people may have two very different results. Consider the example above, but this time from the viewpoint of application support as opposed to server support.

My dedicated log disk filled up last night. Why?

Because someone tried to load ten million rows all at once instead of batching the load into smaller chunks. Why?

Because the bank sent us a huge ass file instead of the normal file. Why?

Because their process created a huge extract by mistake. Why?

I don’t know, but they said it would not happen again. 

So, a different perspective can lead to a different conclusion altogether. To me that demonstrates that the tool itself is subjective to the user, which means it may not be ideal. However, there is something positive from that as well, and that is if you get the different people together in a room you can start to list out all potential root causes and work together on a solution rather than in silos.

Another issue with the tool is that people are only able to find causes they already are familiar with. In the two examples above we reached two different conclusions, but each conclusion was the result of that persons viewpoint and experience. In other words, you know what you know and you don’t know what you don’t know, and the ‘5 Why’ tool will not give you insight into things you don’t know. This also helps to explain why the tool is not a repeatable tool.

A third drawback would be that as a result of the tool only allowing people to find causes they are familiar with means that they will often times stop at symptoms instead of continuing on to the actual cause. All three of this drawbacks I have listed are really just variants of each other, but they are all valid considerations to make when using this technique.

I think the most important aspect to all of this would be to remember that you are only looking for potential root causes. At best, that is what you will find with this tool. And if you keep in mind that the tool is only going to help you get closer to your desired goal, and not the tool that definitively gets you there, then you should be fine. Just consider it as one piece of the puzzle, and not the whole picture.