Causal Loop Diagram Asymmetrical Level Pattern

| 3 min read

I participated in a workshop on System Thinking hosted by Kent Beck (Yep, that Kent Beck) and Jessica Kerr (Yep, the real Jessitron) during NCraft this year.

We draw a lot of causal loop diagrams all together and in sub-groups.

In some diagrams we drew, I started spotting a pattern I found strange, something bothering my appetite for symmetry.


From time to time, we drew diagrams indicating that :

  • more of A leads to more of B, and more of B leads to more of C, and
  • more of A leads to more of C

What felt strange to me is that these diagrams described in two ways that C influences A. One directly and another indirectly, via B.

It looks like path 1, A -> B -> C, and path 2, A -> C, are not on the same level of abstraction. Why do you, on one side, care about that intermediate B step and not on the other?

Seeing that pattern pushes me toward two options, Zooming Out and Zooming In.

Zoom Out

The first option is that the diagram still conveys enough information for our discussion if we remove B. We are then left with a simpler diagram, showing that more of A leads to more of C. We can avoid the clutter and acknowledge that B wasn’t that relevant to the story we’re telling. We don’t need that level of detail, and we can zoom out.


But that’s not always that easy. Maybe B is interesting for our story, and we really don’t want to remove it from the picture.

Zoom In

The other option is to start asking questions and try to zoom in. That imbalance prompts us to look for more details. How does A influence C in other ways? What parts of this story are we missing?


After a few questions, we might discover that A influences C via D, or even via even more complex relationships and have a different look at our system. By noticing that asymmetry, we might gain a deeper knowledge of the problem we are dealing with, and have greater discussions.

Zoom In and Zoom Out later

Choosing between Zooming Out and Zooming In is not an obvious choice.

Why did we include B in the first place? It must have made sense for our discussion and understanding of the system. Before getting rid of it, I feel like we should give a chance to the discovery process and try to Zoom In first. After completing the diagram with the missing parts, we can decide that B and the new details we’ve uncovered are not worth keeping, and finally, Zoom out.

Drawing as many diagrams as needed and not being afraid to throw them away, to try different forms and see what works for your current discussion, was one the first pieces of advice Jessica and Kent shared with us.

It’s about the direction...

Zooming out is only possible if in both paths, A -> C and A -> B -> C, A influences C in the same direction.


  • more of A leads to less of C, but
  • more of A leads to more of B, and more of B leads to more of C (so more of A leads to more of C)


  • more of A leads to more of C, and
  • more of A leads to more of B, but more of B leads to less of C (so more of A leads to less of C)[1]

You definitely should avoid the Zooming Out option and keep that part of the diagram as it is. There is something interesting in the story here. Zooming In could probably be worthwhile to explain how more of A can lead to more of C and to less of C at the same time. You might find an interesting intervention point in your system if you are trying to increase (or decrease) C.

I find it really interesting how noticing a visual pattern of one direct and one indirect path can push us to clarify our drawing or to ask more questions. It is similar to our reflexes while looking at code, noticing patterns that are good opportunities for code improvements or should lead to more inquiry. Being able to pattern match quickly is one of the things you gain with experience (so yay me, more system thinking experience!) and also greatly helps when you are helping others. You quickly notice something and can start asking questions to facilitate the discussion. Maybe that pattern I noticed will be useful to others!

  1. The same idea applies to more of A leads to less of B, but less of B leads to more of C. ↩︎