How To Use Systems Thinking To Understand And Communicate Complex Behaviours

David Plummer
17 min readJan 31

Systems thinking provides a way to model complex behaviours which cannot be analysed with other approaches such as reductionism or linear thinking. Understanding how to describe a system is an essential skill for identifying and communicating why systems behave the way they do.

All images © David Plummer

The system is more than its parts

Science encourages the study of subjects at ever increasing levels of detail. If we can reduce things to their basic components then we will have an explanation for everything. Large amounts of money is spent on grand atom smashers seeking to break the Universe down to its smallest constituent parts. Yet, does the study of these smaller particles bring us any closer to a unified theory of everything? So far the answer is no.

“In the case of all things which have several parts and in which the totality is not, as it were, a mere heap, but the whole is something besides the parts, there is a cause; for even in bodies contact is the cause of unity in some cases, and in others viscosity or some other such quality.” [Metaphysics Book VIII, 1045a.8–10, Aristotle; Translated W.D.Ross 1908]

Aristotle, Greek philosopher (384–322 BC), reasoned that the whole is more than its individual parts. He believed that, in addition to the parts themselves, it was necessary to study how they were structured in order to understand what gives things form.

Systems thinking is about structure. It acknowledges that studying the parts alone is insufficient and a understanding how they relate is also necessary. It seeks to broaden understanding of the the interaction between parts rather than subdividing parts in search of the mythical nugget of truth.

If you want to know how a hospital works, you do not take an individual doctor and seek to understand what they do in ever more detail but instead look at how all the doctors, nurses, other staff, building and information work together to deliver the whole. If you want to know how traffic will flow you do not need to know how vehicles are built, but you do need to know how drivers will react to each other and the road configuration. If you introduce an animal into a habit you don’t need to know more about the animal…

David Plummer

Writing on systems thinking; data analytics in health and care; and anything else that makes the grey cells itch.