Places to Intervene in a System by Donella H. Meadows - developer.*, Developer Dot Star - 0 views
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Folks who do systems analysis have a great belief in "leverage points."
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"Places to Intervene in a System," followed by nine items: 9. Numbers (subsidies, taxes, standards). 8. Material stocks and flows. 7. Regulating negative feedback loops. 6. Driving positive feedback loops. 5. Information flows. 4. The rules of the system (incentives, punishment, constraints). 3. The power of self-organization. 2. The goals of the system. 1. The mindset or paradigm out of which the goals, rules, feedback structure arise.
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Numbers ("parameters" in systems jargon) determine how much of a discrepancy turns which faucet how fast.
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Probably ninety-five percent of our attention goes to numbers, but there's not a lot of power in them.
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Not that parameters aren't important—they can be, especially in the short term and to the individual who's standing directly in the flow. But they rarely change behavior. If the system is chronically stagnant, parameter changes rarely kick-start it. If it's wildly variable, they don't usually stabilize it. If it's growing out of control, they don't brake it.
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Numbers become leverage points when they go into ranges that kick off one of the items higher on this list.
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A delay in a feedback process is critical relative to rates of change (growth, fluctuation, decay) in the system state that the feedback loop is trying to control.
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Delays that are too short cause overreaction, oscillations amplified by the jumpiness of the response. Delays that are too long cause damped, sustained, or exploding oscillations, depending on how much too long. At the extreme they cause chaos. Delays in a system with a threshold, a danger point, a range past which irreversible damage can occur, cause overshoot and collapse.
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It's usually easier to slow down the change rate (positive feedback loops, higher on this list), so feedback delays won't cause so much trouble
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Most systems have evolved or are designed to stay out of sensitive parameter ranges. Mostly, the numbers are not worth the sweat put into them.
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The plumbing structure, the stocks and flows and their physical arrangement, can have an enormous effect on how a system operates.