by Jarrod Coulter

Created on: May 20, 2008

Root cause analysis (RCA) by itself seeks to find what is truly at fault for a given problem. The Information Technology Infrastructure Library provides us with a definition of a problem for which we can base a discussion: A problem is multiple incidents, or a single significant incident, indicative of a single error for which the root cause is unknown.

There are so many tools to use in performing RCA that it can be somewhat confusing. Do you use the 5 Why's, Ishikawa (fishbone) diagrams, or fault tree analysis? All of these methods require too much analysis for one article, so let's start with discussing the pros and cons of using 5 Why's.

The most basic definition of this tool is to ask why as many times as it takes to get to the root cause. You could ask it three times or sixty times, but the general guideline is to ask why something happened five times.

This is about the time when most people have fallen asleep from reading about terminology, so let's take a break from reality and look at a fictional situation where the 5 why's helps us get to the root cause of a problem:

Johnny Incident lived in ITILia with his sister, Sally. Sally always had bruises from bumping into things. Johnny, as the good brother he is, was very concerned for his sister's health as she smacked her head off the wall. Johnny's initial reaction to the symptom was to put a helmet on his sister's head to prevent any brain damage. While this stopped the facial bruising and potential long term effects, Sally continued to bump into things.

Johnny decided to get some help. He called his friend Bobby Problem to figure out what is wrong. Bobby, being the great problem solver he is, used the 5 Why's tool to get to the root of the problem.

Bobby asked Johnny, "Why does your sister have a helmet on?"
"I'm worried she'll get brain damage," replied Johnny.
"Why are you worried about brain damage?" inquired Bobby.
"She has all these bruises and bumps on her head," Johnny said quite concerned.
"Why does she have all those bruises and bumps?" Bobby asked.
"She's always walking into walls and things," Johnny shot back.
"Why is she walking into things?" Bobby wanted to know.
"I don't know," griped Johnny, "because she's a klutz?"
"Why is she a klutz?" Bobby replied.
Johnny started to get irritated, "You know these questions are really starting to pi.."
"Because all I see is blurry blobs!" wailed Sally interrupting Johnny.
"Aha!" exclaimed Bobby. Bobby and Johnny worked together to get Sally fitted for glasses after which she never bumped into anything again.

This simplistic story demonstrates the value and technique of using the 5 Why's as a RCA tool. The technique itself is quite simple and effective as long as the right people are involved in answering the questions. Once you have the root cause defined through the 5 Why's it's probably a good idea to validate or test the root cause to be sure you are still fixing the right part of the process or faulty item.

One note of warning about this tool is to avoid using a template or becoming complacent in using it. Some risks involved are only asking why five times and not going beyond which leaves an opening for missing the real root cause (Note: this can lead to repeat problems which are a huge financial risk). The key to success with this tool is being thorough in your investigation.

So, we've examined RCA, and more specifically one of the tools used to arrive at the root causes. The 5 Why's provides a simple tool to prevent the recurrence of problems in any size organization and at any organization level.

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