In the practice known as Root Cause Analysis (RCA), we are generally looking for reasons to explain why a problem occurred. In most cases, we find that there are many reasons for any given problem. Some (or most?) of them may be far removed in time, space, and subject from the problem itself. We typically call such reasons Root Causes, and according to theory, correcting these Root Causes will prevent future occurrences of this problem, and potentially many others.
The basic RCA method is to simply ask "Why" over and over again until you arrive at a Root Cause. The real question then becomes: how do we know when to stop asking "Why"? At what point are we satisfied that we've identified a Root Cause? What is a Root Cause? These are questions that constantly spark disagreement among RCA practitioners. While there is some disagreement as to what constitutes a Cause, the real fireworks begin when you try to define the word Root.
Dictionary.com has a rather lengthy definition of Root. I won't reproduce it here, but it should suffice to say that there are many different definitions. However, there are a few common meanings that run through most of them:
- Roots are frequently hidden under the surface.
- Roots provide support or act as a base.
- Roots relate to origins and sources.
- Roots are primary and fundamental.
- Roots are established and entrenched.
What about the etymology of Root? According to the Online Etymology Dictionary, Root comes from the Old Norse word rot for "underground part of a plant." The current meanings of Root make sense in this respect. The etymology tells us that when we use the word Root today, we are basically using it as a metaphor to suggest the qualities of plant roots. In addition to the list above, the following qualities come to mind.
- Roots can spread out further than you expect.
- Roots can be hard to find and harder to get rid of.
- Roots that aren't removed may continue growing.
- Roots are often very dirty.
When RCA practitioners talk about Root Causes, they are basically talking about Causes that have all the qualities listed above. They want you to understand that problems are like plants that you don't want, i.e. weeds. If you leave a weed alone, you will end up with more weeds. If you try to remove a weed by cutting it off at the surface, your weed will grow back. The part of a weed you have to kill or remove to prevent future weeds is the root. The best overall solution would be to treat the soil so weeds don't take root in the first place!
So, back to the real questions at hand: what is a Root Cause? At what point are you satisfied that you've found one? When can you stop asking "Why"? Here's a short answer: you're right next to a Root Cause for your problem when you reach a fundamental force, law, or limit that cannot be removed by any action taken within your system. The actual Root Cause is the contradiction between your system's values (purpose, rules, culture, etc.) and these fundamental forces, laws, or limits.
That's all I'm going to say for now, but I'll be exploring this topic in more detail in the future. Keep watching my blog for more articles on this topic.
by Bill Wilson