Stocks are the stuff which a system concerns itself with.

They are physical stores or levels of intangible concepts. Feedback loops monitor stocks, with changes serving as triggers and levels both constituting goals and what enables a feedback loop’s actions. Stocks can either be renewable or non-renewable. Being a part of a system’s goals, stocks are part of a high leverage point in the systemrM3

  1. Donella H. Meadows and Diana Wright, Thinking in Systems: A Primer (White River Junction, Vt: Chelsea Green Pub, 2008). (See notes.)