# What is System Dynamics?

The purpose of System Dynamics is to help people understand complex and dynamic systems and help them make better decisions. The field provides a philosophy and tools to model and analyze dynamic systems. Equally important, the field provides techniques and tools to investigate current decision making and to help decision makers learn.

The purpose of System Dynamics is to help people understand complex and dynamic systems and help them make better decisions.
Photo:
Pexels: Sergio Souza

System Dynamics is a methodology and mathematical modeling technique for strategy development. The main goal is to help people make better decisions when confronted with complex, dynamic systems.

System Dynamics uses simulation modeling based on feedback systems theory that complements systems thinking approaches. It applies to dynamic problems arising in complex social, managerial, economic, or ecological systems.

Systems thinking is a way to describe and understand the causality and interrelations between variables within a system. System Dynamics quantifies the impact of those interactions.

## What do you think is so special about System Dynamics? - John Sterman #shorts

John Sterman, Jay W. Forrester Professor of Management at the MIT Sloan School of Management.

Producer:
System Dynamics Society

See here for an overview of ongoing research projects and here for a selection of student projects in System Dynamics.

### System Dynamics Approach

System Dynamics provides methods and tools to model and analyze dynamic systems. The modeling language is intuitive and lends itself to interdisciplinary work. The basic idea behind System Dynamics is that feedback loops capture the interactions between the system parts and how they lead to a certain overall pattern of behavior over time. The approach focuses on building computer models that bring to light less visible interactions, dynamic complexity, delays, and unintended consequences of decisions and actions.

#### Feedback loops

Feedback loops are chains of cause-and-effect relations that forms a loop where its output routes back to the chain as an input. Hence, these systems feed back into itself. All systems contain feedback loops since all dynamics of systems arise from interactions of feedback loops. Therefore, identifying the feedback loops is at the core of the system dynamics methodology.

Photo:
System Dynamics Group

#### System structure

Components of the system build feedback loops and the relations between these feedback loops are responsible for the behavior of and events in a system. Every system has an underlying structure which determines the behavior of the system. Hence, to understand the system, it is necessary to discover the underlying structure through mapping it.

Photo:
Pexels

#### Modelling and simulation

After mapping the system structure, computers are used to develop a model of the system via quantifying the relations between system components. Then, the model is simulated in computer software to observe the output of the system.

#### Policy design  and strategy development

Observing the behavior of the system with computer simulation allows us to analyse the system and the underlying structure. Hence, it helps us to understand the system better. Having a better understanding of the system provides us with the opportunity of designing policies to solve problems and make better decisions.