Thinking in Systems: A Primer

I went through this again, highlighter in hand. Here are definitions of the major concepts.

A system is an interconnected set of elements, organized is such a way that it achieves… something. This thing can be intended or not.

One of the tricky things about systems is that they’re interleaved, and drift into each other. Systems can exist within systems, and the edges of systems are blurry. Things that “belong” to one system can also belong to another, where they serve the same or a different purpose. So, if you’re talking about “a system,” you’re talking about some set of elements you’ve arbitrarily and artificially isolated in other to speak about a particular thing. In reality, systems are a swirling, interconnected mess.

Systems are built around stocks and flows.

• A stock is a quantified store of something. The balance of your checking account. Your feeling of self-esteem. The water in a bathtub. The number of trees in a forest.

• A flow is the movement of something between stocks, or out of the system. Every stock has an inflow, which is the stuff coming into it (the water from the faucet) and an outflow (the drain in the tub). Flows increase or decrease the amount in a stock. Any stock can have multiple flows both in or out.

Feedback is what causes a flow to turn on or off. A feedback loop is the tendency for the level of a stock to trigger a flow to start or end.

• A balancing feedback loop works to keep the level of a stock within a range. It starts a inflow when the level gets too low, and starts an outflow when it gets too high.

• A reinforcing feedback loop is one that acts in a way that “encourages” itself. For example, it will increase the value of a stock, which will cause the inflow to become greater… which will increase the value of the stock some more.

Time delays in feedback looks cause oscillations of stock levels.

A resilient system is one that modifies itself to maintain balance. It changes its feedback loops – or has meta-feedback loops which change feedback loops – in order to adapt to behaviors.

Bounded rationality says that humans act rationally, but these decisions are bounded by what they can know at any given time. This makes information feedback critically important. Delayed information tightens the boundaries of how humans will act.

The author claims there are 12 leverage points for systems – 12 days we can change how systems work, in increasing order of effectiveness.

1. Numbers: the constants and parameters
2. Buffers: the stabilizing stocks relative to their flows
3. Stock and flow structures: how the physical systems are organized
4. Delays: the lengths of time it takes for feedback loops to trigger
5. Balancing feedback loops: specifically, their strengths
6. Reinforcing feedback loops: again, their strength
7. Information flows: who has access to what information
8. Rules: incentives and punishments
9. Self-organization: the ability of the system to modify itself
10. Goals: what the system is trying to achieve
11. Paradigms: the mindsets and framings that humans managing the system have
12. Transcending paradigms: understanding that paradigms are limiting factors

These have become known as the 12 Leverage Points of Systems.

This is a great book, but I think there’s likely no greater learning experience than to simply diagram some systems yourself.