The System dynamics perspective Flashcards
What is a system?
Interconnected elements that are coherently organized around some purpose
Why do we make systems?
Systems are a human construct made to help try understand and order a complex reality
What is inclusive thinking?
Taking all aspects of the system into account. This includes for instance paramedics and road builders when looking at the car system.
What is important when trying to change the system?
To understand how the system and all it’s feedbacks work, and what its pros and cons are. This allows to change the system to a more desirable form when trying to transition to a different system.
What is Flow?
Flow is the input and output of a system. It is always something per time, etc.
What is Stock?
Stock is the accumulation of Flow that has entered the system and stays there either temporarily or permanently.
How can we influence stock?
In order to influence stock the inFlow and/or the outFlow need to be changed either positively or negatively.
What happens when we influence the inFlow but there is no outflow
Just like with pollution, with only an inFlow stock will accumulate. Decreasing the inFlow will not reduce the stock, it will only increase at a slower rate.
Why are Stock characteristics important?
Stock characteristics are important because it can influence how for example a policy measure works out.
Example: if there was a policy that said that all houses should be ..% efficient, this would be much easier to accomplish with newer houses then with older houses. Therefore the effectiveness of this policy is based on what the stock characteristics are.
Why do systems have inertia?
Because flow capacity can constrain the stock rate.
Three important aspects of a good model
- Feedback structures
- delays
- causal loop diagrams
What is often forgotten when one wants to change something in a system?
All parts of the system can react, either positively by supporting the change or negatively by proposing the change. This all influences how effective the change will be.
What was the general lesson Bert de Vries wanted us to learn from this lecture?
Keep in mind that when you want to change something, the whole system will react. Furthermore, changing the flow does not mean the stock will increase/decrease. Think of what you want to happen to the stock and how to do that.
The system approach is…
an abstract way of looking at what constitutes a part of reality (descriptive) and what determines its evolution in time (analysis, dynamics).
Exponential decline goes…
to a steady state
