 Complexity management may be defined simply as the management of complex systems. So before we can go any further, we really need to give some outline as to what exactly a complex system is. In this video we'll be trying to give a clear outline to the difference between a simple linear system and a complex system. Firstly, complex systems are a type of system. A system is simply a set of things that are interdependent in performing some collective function. So the human body is a system in that it consists of many individual organs that work together as a functioning entirety. A business is another example of a system, many different individuals and departments functioning as an integrated unit to collectively produce some set of products or services. And of course there are many other examples of systems such as transportation systems, ecosystems, information systems and so on. Not everything is a system though. If we take a random collection of things, say a hard drive, a light and a watch and put them together, this is not a system. It is simply a set of elements because they are not interconnected and interdependent in performing some collective function. It is because of the fact that the elements within a system perform some combined function that systems are said to be greater than the sum of their parts. That is to say that the system as a whole has properties and functionality that none of its constituent elements possess. A plant cell would be an example of this. It is composed of many inanimate molecules, but when we put these together we get a biological cell that has the properties of a living system. So it is not any of the elements that have the property of life, but it is the particular way that we arrange these molecules that gives rise to this emergent property of the living system as an entirety. So that is a very quick overview to the idea of a system. The systems can be defined as either simple linear systems or complex non-linear systems. We classify them as such because each have very different properties and behavior and thus how we approach trying to study, design or manage them changes fundamentally. All systems start out simple and they evolve to become complex. Systems have a number of properties that make them more or less complex. These include the number of elements within the system, the level of interdependence between elements, the degree of connectivity between those parts and their degree of autonomy and diversity. Turning these properties to the system up or down makes the system more or less complex. So we'll go over each of these in more detail. Firstly, the number of elements within our system. This is quite straightforward. The more parts there are to our organization, the more complex it will be. In true complex systems, the number of elements is, for all intensive purposes, virtually infinite. Think of the number of devices within a city. It is so many that we could not atomize them. Linear systems consist of a limited finite amount of components where it is possible to know and itemize each element in the system, making it possible to define a closed system and say what is part of that organization and what is not. With complex systems, we typically cannot do this and this is part of what makes them open systems instead of closed systems where we can never fully know and understand all of the parts and all of the interactions, with the internet or financial markets being a good example of this. Secondly, interdependence. Linear systems have a limited amount of elements interacting in a well defined linear fashion, meaning cause and effect are directly related. If I hit a ball with a bat, it will move off in the opposite direction and that is linear causality. It is very simple and intuitive to us. We are programmed to look for and try and understand the well through simple cause and effect interactions like this and this works well when dealing with simple systems. But as we turn up the interdependency between the parts, this linear causality starts to break down. Interdependency means the way we put things together and what we put together matters. By putting two chemical substances together, depending on which ones they are, we may get very different outcomes. They may work together, giving us an outcome much greater than we'd expect or they may have no effect on each other at all. Coupled to this, events may be interdependent over time as they feedback on themselves to have a compounding effect over time. Like compound interest acting on a bank account, the results can be exponential growth or decay and things can change very rapidly. With these feedback loops, small events can get amplified into large systemic effects and this is part of the idea of the butterfly effect and chaos theory. Next, the degree of connectivity is another primary factor. Complex systems are known to be highly interconnected. This is why they are typically modeled as networks that captures the structure of this connectivity. Linear systems have a low level of interconnectivity between their parts and thus we define them in terms of these isolated parts and their properties. In these highly interconnected systems such as the internet or global air transportation system it is the structure of the network that comes to define the system. That is to say what is connected to what and where you lie in the network. Are you a central hub like London in the financial markets or on the periphery of the network? What is flowing on the network? How evenly is the connectivity distributed out? And many other questions relating to the structure of the connections. Connectivity and access are central to understanding complex systems and network theory is the language through which we do this. Lastly complexity is also a product of the degree of autonomy and the capacity for adaptation of the elements within the organization and a corollary to this is diversity. When all the elements within our system are very similar or homogeneous then it is much simpler to model, design or manage as opposed to dealing with a heterogeneous organization composed of many diverse parts each with their own unique set of properties. When the elements have a very low level of autonomy and diversity then the system can be designed, managed and controlled centrally in a top-down fashion. But as we increase the autonomy of the elements within the system this becomes no longer possible as control and organization become distributed out and it is now the interactions on the local level that comes to define how the system develops. And this gives rise to an important feature of complex systems that is self-organization. When elements have the autonomy to adapt locally they can self-organize to form global patterns of organization. The process through which this takes place may be called emergence. Thus as opposed to simple linear systems where order typically comes from some top-down centralized coordination patterns of order within complex systems emerge in a distributed fashion from the bottom up. In this video we've been briefly laying down a working definition for what a complex system is. We defined it as a system composed of multiple interdependent parts that are highly interconnected and capable of autonomous adaptation. To cite a few more examples we might think of financial markets with lots of different highly interconnected traders adapting to each other's behavior as they interact through buying and selling securities or an ecosystem with multiple different species that are all interdependent and adapting to each other and their environment. Another example would be a supply chain network with many different products and distributors interacting and adapting to each other in order to deliver a product. And there are many more examples of complex systems such as transportation networks, cities, the human brain, the weather and many types of social organizations.