Many systems have processes with time-lag in their behaviour. Changes to systems’ behaviour do not occur immediately when a change to the inputs or transformation process is made.   Changes can take significant amount of time to take effect, therefore can be difficult to predict system behaviour. Unintended changes might not become apparent for significant amount of time e.g. human […]


Many systems display non-linear behaviour i.e. their outputs are not directly proportional to their inputs. Non-linear systems do not satisfy superposition principal, or superposition property. For all linear systems, net response at given place and time caused by two or more stimuli is sum of responses which would have been caused by stimuli individually. If input A produces response X and input […]

Holistic and Reductionist views

Holistic Concept that system is greater than the sum of its parts, see the Bicycle and Central Heating systems for examples. Trying to identify all connections to systems environment, view is limited to that environment. By looking beyond the holistic or systemic view, we would be considering the ecological view recognising “the fundamental interdependence of all phenomena and the fact […]


System in some way performs a transformation on its inputs from the environment and then sends them as outputs back to the environment. Transformation occurs to support system purpose, goals and objectives. No transformation then no system.  

Perspectives and Stakeholders

It is vital to identify stakeholders and their level of interest in the system. Different stakeholders may have different perspectives – a view on something at a point in time. Perspectives can change in light of new information or change in circumstance. Example: Perspectives of a bicycle Environmentalist – mode of transport with minimal impact on environment Ecologist – considers […]

Dynamic Equilibrium

Concept of system keeping itself in a steady state. Control and feedback loops provide inputs into this concept. Concept suggests system has management capabilities to maintain dynamic equilibrium. If dynamic equilibrium not maintained, system may cease to function or may function in a manner that does not meet purpose, objectives or goals. Example: British political system Has adapted to many […]


Example of emergence: Central Heating System. Components are radiators, boiler, water, thermostat and pump. Collection of components provide no functionality. When organised and interconnected in specific way they form a system with emergence of heat and hot water. The thermostat is the control mechanism, inputs from the environment are how warm it is and how hot the water is. Switches […]


Hierarchy determines the graded levels of systems and sub-systems. Need to decide how many levels of hierarchy to analyse: too few results in any overly simplistic analysis resulting in interconnections and complexity being misunderstood too many results in any overly complicated analysis resulting in too much detail obscuring key interconnections Example: Consider a school as a system Within the boundary […]

Environment and sub-system

Environment is context in which system operates and is major influence on system behaviour. System receives inputs from and provides outputs to environment. Systems change overtime. “What does the system interact with?” – no absolute answer. Depends on perspective taken. The same applies to the boundary too. Stakeholders have one view but asking whole group helps identify those elements that […]


Identifies limits of the system. Definition of boundary relates directly to system’s purpose. Inside boundary are elements/components that make up system and are within system’s control. Outside boundary is environment and the elements/components that are outside of the system’s control. Elements/components both inside and outside boundary can be used as system inputs and can also be influenced by it’s outputs. Analysing […]