System Dynamics

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System Dynamics (SD) or system dynamics is a methodology developed by Jay W. Forrester at the Sloan School of Management at MIT in the mid-1950s for the holistic analysis and (model) simulation of complex and dynamic systems .

It is used in particular in the area of socio-economic systems . In this way, the effects of management decisions on the system structure and system behavior, such as corporate success, can be simulated and recommendations for action can be derived. In practice, the method is used in particular in the design of learning laboratories , in strategic and operational planning and the operationalization of balanced scorecards . The analysis and design of socio-economic facts and problem situations is carried out using qualitative and quantitative models.

Qualitative models

The qualitative method is mainly about the identification and investigation of closed chains of effects ( feedback loops ). A distinction is made between loops with positive ( reinforcing loops ) and negative ( balancing loops ) polarities . Originally, u. a. According to Forrester, the qualitative method should always be supplemented by a subsequent quantitative analysis (simulation): In fact, for conceptual or financial reasons, today's system dynamics projects are partially limited to qualitative models. Qualitative models such as causal diagrams or "influence diagrams" make an important contribution to system analysis even without simulation and the use of "hard data" (Wolstenholme EF. 1993): They summarize a very complex problem, consisting of innumerable explanations, in a clearer way Way together and help as a template for discussions. They identify feedback and thus help to explain problems and structures or to gain new insights. Examining the diagram may better reveal the appropriateness of the model boundaries and assumptions. And finally, they serve as the basis for possible quantitative models, especially since they can be transformed into equations with relative ease.

Quantitative models

The presentation in flow charts and their simulation enables a deeper understanding of the system. Stock ( Stocks ), rates ( flows ) and auxiliary variables used to describe the system context and show how complete the functional chains on the behavior of systems that are and counterintuitive partly non-linear. This is the main advantage of this method. Special software such as CONSIDEO, simcision, AnyLogic , iThink / STELLA, DYNAMO , Vensim, Powersim or cadCAD enable the simulation of the questions examined. The simulation of different scenarios ( runs ) promotes the understanding of the system behavior over time.

The recurring behavioral patterns of complex systems are based on certain structures that can be represented as simplified models, so-called system archetypes . There are currently 10 different such system archetypes. Knowledge of these basic structures enables a deeper understanding of various systems and thus creates a basis for more effective interventions in them.

Applications

Nowadays, System Dynamics is used in particular in the areas of economics and business administration to analyze dynamic and complex issues. Examples come from the public and private sectors: production management, strategic planning, analysis and design of business models, business forecasting and scenario analysis. The methodology is generally suitable for simulating and explaining the complex behavior of people in social systems . Typical examples here are overfishing of the world's oceans or the emergence of disasters, e.g. B. the Chernobyl disaster . System Dynamics was also the basic methodology for simulating the world model World3 that the studies on Limits to Growth (dt .: The Limits to Growth , 1972) under the leadership of Dennis Meadows on behalf of the Club of Rome was created. Important simulation models, especially for environmental research, were developed by Hartmut Bossel .

findings

In addition to the model and the solution approaches themselves, the knowledge gained and the understanding of the processes are also results that are used beyond the project. Understanding the method also leads to improved and faster knowledge of other problems.

literature

Web links

Commons : Systems dynamics  - collection of images, videos and audio files

Individual evidence

  1. ↑ Jay Forrester: Counterintuitive behavior of social systems. In: Technology Review. 73 (3) 1971, pp. 52-68.
  2. ↑ Geoff Coyle: Qualitative and quantitative modeling in system dynamics: some research questions. In: System Dynamics Review. 16 (3) 2000, pp. 225-244, doi : 10.1002 / 1099-1727 (200023) 16: 3 <225 :: AID-SDR195> 3.0.CO; 2-D
  3. ^ Erling Moxnes: Not only the tragedy of the commons: misperceptions of feedback and policies for sustainable development . In: System Dynamics Review . tape 16 , no. 4 , January 26, 2001, ISSN  0883-7066 , p. 325-348 , doi : 10.1002 / sdr.201 .
  4. ^ Markus Salge, Peter M. Milling: Who is to blame, the operator or the designer? Two stages of human failure in the Chernobyl accident . In: System Dynamics Review . tape 22 , no. 2 , 2006, ISSN  1099-1727 , pp. 89–112 , doi : 10.1002 / sdr.334 .