Simply put, a system is an organized collection of parts (or subsystems) that are highly integrated to accomplish an overall goal. The system has various inputs, which go through certain processes to produce certain outputs, which together, accomplish the overall desired goal for the system. So a system is usually made up of many smaller systems, or subsystems. For example, an organization is made up of many administrative and management functions, products, services, groups and individuals. If one part of the system is changed, the nature of the overall system is often changed, as well -- by definition then, the system is systemic, meaning relating to, or affecting, the entire system. (This is not to be confused with systematic, which can mean merely that something is methodological. Thus, methodological thinking -- systematic thinking -- does not necessarily mean systems thinking.)
Systems range from simple to complex. There are numerous types of systems. For example, there are biological systems (for example, the heart), mechanical systems (for example, a thermostat), human/mechanical systems (for example, riding a bicycle), ecological systems (for example, predator/prey) and social systems (for example, groups, supply and demand and also friendship). Complex systems, such as social systems, are comprised of numerous subsystems, as well. These subsystems are arranged in hierarchies, and integrated to accomplish the overall goal of the overall system. Each subsystem has its own boundaries of sorts, and includes various inputs, processes, outputs and outcomes geared to accomplish an overall goal for the subsystem. Complex systems usually interact with their environments and are, thus, open systems.
A high-functioning system continually exchanges feedback among its various parts to ensure that they remain closely aligned and focused on achieving the goal of the system. If any of the parts or activities in the system seems weakened or misaligned, the system makes necessary adjustments to more effectively achieve its goals.
A pile of sand is not a system. If you remove a sand particle, you have still got a pile of sand. However, a functioning car is a system. Remove the carburetor and you no longer have a working car.
Systems Theory: the transdisciplinary study of the abstract organization of phenomena, independent of their substance, type, or spatial or temporal scale of existence. It investigates both the principles common to all complex entities, and the (usually mathematical) models which can be used to describe them.
Five disciplines to cultivate systems thinking, according to Peter Senge:
1) systems thinking
2) personal mastery
3) mental models
4) building shared vision
5) team learning
Twelve principles for managing change:
1) Thought processes and relationship dynamics are fundamental if change is to be successful.
2) Change only happens when each person makes a decision to implement the change.
3) People fear change it "happens" to them.
4) Given the freedom to do so, people will build quality into their work as a matter of personal pride.
5) Traditional organizational systems treat people like children and expect them to act like adults.
6) "Truth" is more important during periods of change and uncertainty than "good news."
7) Trust is earned by those who demonstrate consistent behavior and clearly defined values.
8) People who work are capable of doing much more than they are doing.
9) The intrinsic rewards of a project are often more important than the material rewards and recognition.
10) A clearly defined vision of the end result enables all the people to define the most efficient path for accomplishing the results.
11) The more input people have into defining the changes that will affect their work, the more they will take ownership for the results.
12) To change the individual, change the system.