Originated by Jay W. Forrester (Industrial Dynamics, 1961), best known through Donella H. Meadows, Dennis L. Meadows, Jørgen Randers, and William W. Behrens III (The Limits to Growth, 1972).
Represents a system as quantities that accumulate and the rates that fill or drain them, then simulates the model forward to show behavior over time.
When to reach for it
Delays and accumulations drive the problem (inventory, headcount, backlog, cash), and a question of how much and when needs numbers, not arrows alone.
How it runs
- Set the boundary of what the model includes.
- Name the stocks that build up over time.
- Name the flows that raise or lower each stock.
- Write the equations and estimate starting values.
- Simulate, then check the output against past behavior.
- Run the policy changes under consideration as scenarios.
Where it sits in SOLVE eX
Go to the source
- Industrial Dynamics, 1961
- The Limits to Growth, 1972