System Dynamics

System Dynamics

System dynamics models complex systems with continuous simulation and feedback loops.

Feedback Loops

Positive (reinforcing) amplifies change. Negative (balancing) drives toward equilibrium. Most systems have multiple loops.

Stock and Flow

Stocks are accumulations. Flows fill or drain stocks. Auxiliary variables and constants influence flows.

Causal Loop Diagrams

Show cause-effect relationships. Polarity +/- indicates direction. R (reinforcing) or B (balancing) loops.

Differential Equations

dStock/dt = Inflow - Outflow. Euler and Runge-Kutta for numerical integration.

Tools

Vensim, Stella, AnyLogic, Python with SciPy.

Applications

Population dynamics, epidemics, business strategy, supply chain (bullwhip effect), urban planning.

Summary

System dynamics models feedback loops, stocks, and flows for strategic-level understanding.