Rich Pictures are simply pictorial representations of the relations between a number of relevant elements. The strength of rich pictures is that they're free form without any formal rules, which also tends to be the shortcoming of rich pictures.
Once I get the formulas and get this working unfold the story and exercise the 2 stock model and then surface the other two stocks and exercise the mode then.
Add variables so I can use sliders to control the multipliers in the flows and the initial values of the stocks.
This model is an attempt to understand the interactions within an economy in an attempt to determine where the leverage points are to stimulate an economy.
Part 1 demonstrates Picture primitives and Links to create representations of interactions. These are made visually attractive because the Picture primitives are overlayed with images.
Inventory Model v2.0 adds production and order lead time. As well as the ability to keep track if parts are on order for a production run. See also: Inventory Model v3.0.
An escalation structure results from two or more competing entities with the competition taking them to somewhere none of them want to be. See also Archetypes.
A Growth and Underinvestment structure is simply an elaborated Limits to Growth structure where the growth inhibitor is part of another Balancing Loop with an external standard and some delay. The real nasty thing about this structure is that the two Balancing Loops form a single Reinforcing Loop which inhibits growth.
There are limits to what one can infer from a qualitative model. It is typically beyond the capacity of humans to infer the behavior of complex situations with 2 or more feedback loops.
There is much we can learn from the development of qualitative relationships models though once we begin to ask questions like how long, how much, when, etc., a qualitative most is not likely to be of much use. The following video demonstrates how, in a very simple goal-seeking structure with delay, depending on the delay, it can be almost impossible to intuit the implications of the interactions with any level of accuracy. The difficulty arises essentially from operating with outdated data. See also Archetypes.
Simple bathtub model to show the difference between Stock and Flow. Run the model with various values for filling and draining to see the implications.
