Structure produces behavior.

One stock, two independent flows. The level only tracks inflow minus outflow — it has no idea how full it already is.

Leverage point #10 Stock & flow structure

The inflow is a function of the stock: more balance → more interest → more balance. The loop feeds itself.

Leverage point #7 Reinforcing-loop gain

The gap between the coffee and the room drives the outflow. As the gap shrinks, the flow shrinks.

Leverage point #8 Balancing-loop strength

Same balancing loop as the coffee — but the sensor reads a delayed temperature, so the heater keeps acting on stale information.

Leverage point #9 Delays

A balancing loop chasing a goal — but the goal itself drifts down toward whatever performance you're already getting. Standards adjust to reality instead of reality rising to the standard.

Leverage point #3 Goals

Two stocks locked together. Prey reproduce on their own (a reinforcing loop); predators eat prey and starve without them (a balancing loop). Neither has a fixed goal — each is the other's controller.

Leverage point #8 Balancing-loop strength

Two competitors draw from one shared pool, split by an allocation rule that favors whoever is already ahead. The lead feeds the rule, the rule feeds the lead — a reinforcing loop with a tiny head start.

Leverage point #5 Rules

One shared stock regrows on its own (a balancing loop toward carrying capacity) while many harvesters drain it for private gain (a reinforcing pull toward collapse). No harvester sees the aggregate draw.

Leverage point #6 Information flows

A reservoir between a jumpy inflow and a steady downstream demand. The level rises and falls; what flows out is the level divided by the buffer — so the bigger the store, the more it averages the bumps away.

Leverage point #11 Buffer sizes

Two rivals, each arming to stay ahead of the other. Every buildup one side sees becomes the reason for its own — two reinforcing loops pointed at each other.

Leverage point #7 Reinforcing-loop gain

One stock pulled toward two incompatible goals at once — reformers hauling it up, resisters hauling it down. Each pulls harder the further the stock sits from its own target.

Leverage point #8 Balancing-loop strength

A problem relieved two ways: the system's own capacity, or an outside intervention. The intervention works — but leaning on it lets internal capacity wither, so the problem needs the intervention even more.

Leverage point #9 Delays

Effort optimizes a measured target as hard as it's set. But true welfare follows the measure only up to a point — past the peak, more of the metric makes things worse.

Leverage point #3 Goals

A stock closing on a target. One knob sets how fast it adjusts (a parameter); the other sets the target itself (the goal).

Leverage point #12 Parameters

Two strategies competing for one population. Each grows in proportion to how its fitness beats the average — no central planner picks the winner.

Leverage point #4 Self-organization

Effort is rewarded for the measured metric, not the real outcome. When the metric is easy to game, hitting the target and achieving the goal come apart.

Leverage point #5 Rules

A population living off a renewable resource. The population grows on what the resource provides; the resource regrows on its own and is drawn down by the population. The catch: the resource refills slowly, so the population only feels the limit after it has overshot.

Leverage point #9 Delays

An economy that reinvests its profits to harvest a renewable resource. More capital means more harvest; more harvest means more profit to build more capital. The resource regrows on its own — but only so fast.

Leverage point #8 Balancing-loop strength

Output grows toward whatever input is scarcest — not the sum of inputs, the minimum. Water, nutrients, light: the smallest one sets the ceiling.

Leverage point #10 Stock & flow structure