2.4 System variables and Parameters

Some parts of a system are under direct management control, while others are not. This is
measured with respect to values in the system variable and parameters.
System variable - item controlled by decision-maker

Example: The price a company charges for its product is a system variable
because it can be controlled.
System parameter - value that cannot be controlled

Example: the cost of a raw material.
The number of pounds of a chemical that must be added to produce a
certain type of plastic is a quantity or value that is not controlled by
management; it is controlled by the laws of chemistry.