Editing System dynamics (section)

===Stock and flow diagrams===
{{Main article|Stock and flow}}
Causal loop diagrams aid in visualizing a system's structure and behavior, and analyzing the system qualitatively. To perform a more detailed quantitative analysis, a causal loop diagram is transformed to a [[stock and flow]] diagram. A stock and flow model helps in studying and analyzing the system in a quantitative way; such models are usually built and simulated using computer software.

A stock is the term for any entity that accumulates or depletes over time.  A flow is the rate of change in a stock.

[[Image:Simple stock and flow diagram.gif|centre|frame|A flow is the rate of accumulation of the stock]]

In this example, there are two stocks: Potential adopters and Adopters.  There is one flow: New adopters.  For every new adopter, the stock of potential adopters declines by one, and the stock of adopters increases by one.

[[Image:Adoption SFD.png|centre|Stock and flow diagram of ''New product adoption'' model|frame]]