Editing System dynamics (section)

===Equations===
The real power of system dynamics is utilised through simulation.  Although it is possible to perform the modeling in a [[spreadsheet]], there are a [[Comparison of system dynamics software|variety of software]] packages that have been optimised for this.

The steps involved in a simulation are:

*Define the problem boundary.
*Identify the most important stocks and flows that change these stock levels.
*Identify sources of information that impact the flows.
*Identify the main feedback loops.
*Draw a causal loop diagram that links the stocks, flows and sources of information.
*Write the equations that determine the flows.
*Estimate the parameters and initial conditions.  These can be estimated using statistical methods, expert opinion, market research data or other relevant sources of information.<ref name="Sterman2001CMR">{{cite journal |last=Sterman |first=John D. |year=2001 |title=System dynamics modeling: Tools for learning in a complex world |journal=California Management Review |volume=43 |issue=4 |pages=8–25|doi=10.2307/41166098 |jstor=41166098 |s2cid=4637381 }}</ref>
*Simulate the model and analyse results.

In this example, the equations that change the two stocks via the flow are:

 <math> \ \mbox{Potential adopters} = - \int_{0} ^{t} \mbox{New adopters }\,dt </math>
<!-- I don't want to mark up this great contribution, but shouldn't this be something like potential adopters at t(0) - sum(new adopters at t(i))? Yes -->
 <math> \ \mbox{Adopters} = \int_{0} ^{t} \mbox{New adopters }\,dt </math>