Web of Causation and why I don’t like 5 Whys

Before we start, I have to add, that I don’t like 5 Whys how I have seen it often done. This is my personal, not very exhaustive experience. Maybe your experience is different. In that case, please take a moment and think about what you do differently and how that makes it a more successful approach.

Why do I not like 5 Whys?

In my experience, the 5 Whys approach is almost always used in a linear approach.

Why is it not good to use a linear approach?

A linear approach digs deeper into one direction of what we believe from the start is the root cause.

Why is digging deeper not a good approach?

Digging deeper is a good approach. Remember the post about “zooming in” from last week?

Why is digging into one direction not a good approach?

Things don’t just happen! Let me tell you about the web of causation or web of causality. As a systems thinker I try to see the connections and dependencies between nodes in the system at hand. Nodes might have obvious connections between each other. Or they have more indirect connections, not that obvious to spot on first sight.

So digging is good, but you have to look sideways and around corners as well. You might change direction, or split up and go into different directions at the same time. Of course you can do it sequentially. What I try to say is, there will often be more than one factor.

The web of causation tries to show the relations of different nodes in a system and how they interact and influence each other. The resulting web might look complex by itself. But that is the issue. We often look into a failure of a complex system. And with 5 Whys we try to determine the one root cause.

In my experience, there is a weird fascination of people with one root cause. Why can’t there be two or more? Well there can be and there will be. And we should acknowledge that. A root – of a plant – is not one thing. A root is a huge complex system by itself. We only treat it too often as one thing. And quite often I have heard when listing a set of causes for a problem, that I need to narrow it down to one. Sometimes they allowed me two.

Why did you stop at 4 Whys?

There is no rule to ask exactly 5 times Why. Sometimes it’s more, sometimes it’s less. If you ask too often, the Big Bang is the root cause. Without it, we wouldn’t be in this situation. Helpful? Not at all.

Are there better ways?

I have not done that many formal root cause analysis to have the ultimate answer to this. One way I prefer over 5 Whys is the Ishikawa or fishbone diagram. It’s a simple way to list many aspects of the system that belong to the incident to analyze. Out of the box it forces you to think multi-dimensional by listing many components like process, people, equipment, and mission. It acknowledges the complexity of the system from the very start.

Each branch is looking at one main aspect of the system and then splitting up into its parts again. It’s a way to dissect the system and look into many directions. It doesn’t try to reduce the search to one root cause. It accepts complexity as given.

The Ishikawa diagram has downsides as well. It quickly becomes unreadable like many mind maps. It lacks a good way to connect the dots. Because each branch will have dependencies to nodes of other branches. We are operating in 2D again, where four dimensions is what you need.

Don’t over-complicate; Goldilocks!

The search to identify the web of causation, all elements that were involved in the failure, might be too time-consuming. Find the right level of abstraction. Look left and right, look up and down, and back and front. Come to a conclusion that is actionable.

You can dig deep and land on a decision that person A made 3 years ago. Not helpful today. Also, the decision was not corrected for 3 years. So what about all the decisions to not do something? You can dig very deep. Systems thinking allows you to do that, and to build your mental model, you ultimately will do that. If you want or not.

But when performing a root cause analysis, please, don’t over-complicate. I tend to do that fairly easy, because I see many of these connections. On the other hand I also don’t see many many more connections. Not everything that is in your mental model has to end up in the analysis. But using a multi-directional approach keeps your mind open to understand that there is often more than one reason. Not only the obvious one.

Just fix it!

At the end a small tip. There are issues where you don’t need to make a complete root cause analysis. Just fix it! Life is complex enough as is. We don’t need to learn from every faulty situation. Often individuals learn enough by just fixing it. Don’t over-formalize. Keep it simple.