Systems Thinking term Synonyms
(*term used by
STELLA
software)
Definition
System An entity composed of diverse but interrelated parts that
function as a complex whole
Component Individual parts of a system; can be a reservoir, an
attribute of a system, or a subsystem
Couplings Links between system components; can be either positive
(a change in one component causes a change in the same
direction in the linked component) or negative (change in
one component stimulates a change of the opposite
direction in the linked component)
State A set of attributes that characterize the system at a
particular time
Flux Input/Output
Flow*
Transfer
Converter*
The rate of matter or energy movement (amount per unit
time)
Reservoir Stock*
Pool
Storage
A place where matter or energy resides
Cycle Constant movement of material from one reservoir to
another
Sink If the flux of matter or energy into a reservoir is greater
than the flux out, the reservoir is a sink
Source If the flux of matter or energy out of a reservoir is greater
than the flux in, the reservoir is a source
Feedback A self-perpetuating mechanism of change and response
to that change
Negative feedback loop Balancing Diminishes the effect of disturbances
Positive feedback loop Reinforcing Amplifies the effect of disturbances
Response time The length of time for a system to return to steady state
after being perturbed
Residence time The length of time a substance remains in a given
reservoir
Threshold Tipping point
The level or value at which a rapid change in the system
state, often from one equilibrium state to another, occurs
Perturbation
A temporary disturbance of a system
Forcing Driver
Cause
A persistent disturbance of a system
Response Effect Change in a system as a result of perturbation or forcing
Equilibrium state Describes whether a system is stable (disturbances from
equilibrium will be followed by system responses that
return the system to its equilibrium state; results from
