systemdynamiske

Systemdynamiske is a Danish term for the field commonly known in English as system dynamics. It refers to the study and modeling of complex, feedback-driven systems to understand how their structure influences behavior over time. The approach originated in the 1950s with Jay W. Forrester at MIT and has since been applied in business, government, and academia.

Core concepts include stocks and flows (accumulations and rates of change), feedback loops (reinforcing and balancing), time delays, and nonlinear relationships. Diagrams called stock-and-flow diagrams and causal loop diagrams help represent the components and interactions of a system. Equations, often differential or difference equations, formalize the relationships and enable simulation.

Modeling process involves problem articulation, model construction, data collection, calibration, validation, and policy testing or scenario analysis. Software tools such as Vensim and Stella are commonly used.

Applications are broad: corporate planning, supply chains, energy and environmental policy, population dynamics, healthcare, urban systems. The method supports exploring policy interventions, long-term behavior, and unintended consequences. Critics note that models are simplifications and may rely on subjective structural assumptions, require data, and may overstate predictive power; proper validation and scenario analysis are essential.