What are the three core elements of a system?
- Elements: Indivisible units of function (e.g., players, ball).
- Interconnections: How elements interact (e.g., rules of the game).
- Function/Purpose: The macroscopic behavior (e.g., to win, to exercise).
How does changing the different components affect the system?
• Elements: Least effect. System remains recognizable (e.g., changing players).
• Interconnections: Major effect. Can change how the system works (e.g., changing the rules).
• Function: Greatest effect. Changes the total outcome and behavior (e.g., playing to lose rather than win).
What algorithm can be used to deduce if something is a system?
- Identify the parts.
- Do the parts interact?
- Is the effect of the interaction different from the effect of the parts in isolation?
- Is the behavior persistent over time?
Define Stock and Flow.
Stock: The accumulation of elements over time (the integral/history). E.g., water in a tub, population.
Flow: The process by which Stocks change (the inputs and outputs). E.g., draining water, births/deaths.
What is Dynamic Equilibrium?
A state where total inflows equal total outflows, keeping the Stock constant.
Why is it significant that Stocks change more slowly than Flows?
It creates buffers. It allows systems to be temporarily out of balance (disequilibrium) without collapsing. It creates time delays, allowing time for corrective action but also causing potential overreaction.
What is a Feedback Loop?
A closed chain of causal connections where the Flow depends on the current level of the Stock.
What is a Balancing Feedback Loop?
A goal-seeking loop that resists change to maintain a Stock within a specific range. It stabilizes the system (e.g., a thermostat or maintaining caffeine levels).
What is a Reinforcing Feedback Loop?
A loop that amplifies change in whichever direction it is moving. It drives exponential growth or collapse (e.g., compound interest or inflation).
What is the approximate doubling time for a reinforcing loop?
Doubling time ≈ 0.7 / growth rate. (E.g., 7% growth doubles in 10 years).
What causes oscillations in a system?
Delays in balancing feedback loops. The system takes time to perceive a change and correct the Flow. By the time the correction takes effect, the Stock has overshot the goal, leading to a cycle of over-correction.
What is ‘Bounded Rationality’?
The concept that decision-makers do not have complete information. They make “rational” decisions based only on the narrow information and incentives available to them locally, which often leads to sub-optimal system results.
What is a Limiting Factor?
The specific input that is currently most restricting to the system’s growth. As the system grows, the limiting factor will shift (e.g., from needing nitrogen to needing phosphorous).
What is ‘Policy Resistance’?
When a policy attempts to change a stock, but the actors within the system adjust their actions to return the stock to its previous level (e.g., Romania banning abortion led to illegal abortions to maintain family size).
What is the ‘Drift to Low Performance’?
A negative reinforcing loop where goals are allowed to erode slowly over time based on past performance. Lower performance leads to lower expectations, which leads to further lower performance.
What is ‘Escalation’?
A reinforcing loop where the stock of one system is determined by the stock of a competitor. Each tries to surpass the other, leading to an exponential spiral until breakdown (e.g., an arms race).
What is ‘Success to the Successful’?
A reinforcing loop where winners receive the means to win more easily in the future, decreasing competition (e.g., interest compounding for the rich vs. interest payments for the poor).
What is ‘Addiction’ (Shifting the Burden)?
A balancing loop where a system transfers responsibility for a problem to an external intervener. This weakens the system’s internal ability to solve the problem, requiring more external intervention (e.g., using drugs for happiness rather than solving life problems).
What is Resilience?
The ability of a system to maintain structure and repair itself after disturbance. It relies on strong balancing feedback loops.
What are the benefits and risks of Hierarchies?
Benefit: Efficient information transfer; subsystems can function partially if links break.
Risks: Suboptimisation (subsystem goals override system goals) and Overcontrol (top layers micromanaging lower layers).
What are Leverage Points?
Places in a system where a small change can lead to a large shift in behavior.
Why are buffers (large stocks) low leverage points?
They stabilize the system but are hard to change physically. They only affect the speed of reaction, not the direction or outcome.
Why is information flow a high leverage point?
Adding a missing feedback loop by delivering information to the right place can spontaneously correct behavior without expensive physical changes (e.g., showing pollution data to decision-makers).
What is the highest leverage point in a system?
Paradigms. Changing the underlying assumptions or goals of the system transforms all lower-level rules, flows, and structures.
