Use the Implicit Goal-Seeking Process
whenever you want to represent a flow of
activity that adjusts a Stock toward an implicit goal. Like the Stock-Adjustment
Process, the Implicit Goal-seeking process describes the result of a production
process, but leaves unstated the resources and productivity required to actually
produce the flow. In addition, this process does not make explicit the goal being
sought. The two inputs to this process are the Stock and an adjustment fraction.
The flow is generated as the product of the two. The adjustment fraction is usually a
graphical function that depends on some other condition(s) within your model.
When the other condition is at its goal, the adjustment fraction is zero. When the
other condition is out-of-line with its goal, the adjustment fraction will take on
positive or negative values — depending upon whether the condition is greater or
less than its goal. As the other condition moves further out-of-line, the adjustment
fraction takes on larger values. Thus, the flow can either increase or decrease the
value of the Stock, depending on whether the adjustment fraction is positive or
negative.
Algebraic Form:
adjustment flow = Slock * adjustment fraction
(units/time) = units * (units/unit/time)
The adjustment fraction typically is a
graphical function that depends on some other
condition within your model.
The behavior of the Implicit Goal-Seeking
Process depends on movements in the
input to the adjustment fraction. As such, there is no one characteristic behavior
pattern associated with the process. However, if the adjustment fraction is a
constant positive value, the process acts like a Compounding Process. If the
adjustment fraction is a constant negative value, the process acts like a Draining
Process.
One common use of the Implicit Goal-Seeking
structure is to represent a pricing
policy, in which producers change the price of a good whenever inventory is not in
line with its desired level. The examples below illustrate other uses of the Implicit
Goal-Seeking structure.
