If you are going to write a blog about complexity science sooner or later you have to define, or at least describe, what you mean by that. And, I'm afraid, my time is now. My reticence is due to the many who have tried and, basically, failed to write a useful definition. Saying that complexity science is the study of complex systems isn't any help -- what's a complex system? Wikipedia's discussion of complex systems is interesting but declines to offer a definition.
So I was excited to see this article in the Harvard Business Review. The authors
". . believe the time has come to broaden the traditional approach to leadership and decision making and form a new perspective based on complexity science."
I love that! However, while their description of complexity science has some things to like, it reads like a laundry list of buzz words. And then there is this assertion:
". . .in a complex system the agents and the system constrain one another, especially over time. This means that we cannot forecast or predict what will happen."
Seems to suggest that we should give up all hope! If you've read my post on Strategic Planning then you know that I believe that we can take effective management action in complex systems and create a surprising level of predictability.
From my perspective the defining characteristic of a "complex system" is that it produces complex dynamic behaviors from the interaction of its parts.
Let's focus on the "produces complex dynamic behaviors . . " part first. There is a pretty simple "know-it-when-you-see-it" type test for this. Draw a time series chart of the things that you are interested in (eg: revenue, sales, new customers, market share, whatever ) over the time period you are interested in. These are dynamic behaviors. Are there any turning points? How about exponential growth or decay? Is anything oscillating? Are there time lags evident from related time series? These things are hallmarks of complex behaviors.
Now let's focus on ". . .the interaction of its parts." The idea here is that the behaviors are endogenous and not pre-stored or pre-programmed into a component of the system. Sometimes this property is called "emergence." The specific way the components interact is the system structure.
This definition identifies "dynamic complexity" as the determining factor as opposed to "detail complex."
Therefore, it is not required that there be a large number of interacting components. Sometimes the system of interest has hundreds or thousands or more components interacting and sometimes it has ten.
There is a secret here and since you've read this far I'll tell you what it is. Most complex systems have a feedback structure that creates the interesting behaviors. And, very often, there is a human making a decision in that feedback loop. That's what makes this perspective so powerful and important.
