“Stocks” are a part of systems design I hadn’t really had a word for before reading Thinking in Systems. They are some quantifiable aspects to a system that can grow or shrink. Stocks are subject to flows. Flows take time. Stocks therefore introduce a delay.
A bathtub has a stock of water. You can increase the stock by turning on the faucet, you can decrease the stock by draining it. You can have static equilibrium where no flow is happening. Or you can have dynamic equilibrium where the inflow and outflow are perfectly matched, the volume of the stock staying the same despite flows in and out. This would be the tub that’s filling and draining at the same rate.
Example Stocks
- Temperature in a toom
- Caffeine in you
- Employee headcount
- Money in your account