Quiz: Stocks and Flows

A quiz about stock and flows.

Stocks and flows (or alternatively levels and rates) are the fundamentals of feedback loops in system models. Stocks reflect the current state of the system i.e. if you know the stock for a certain time step, you can fully describe the system at this point in time. Stocks will not change instantaneously but gradually over time with respect to the flows into and out of the stocks (Martin 1997). Remember the example from the bathtub: the change of the water in the bathtub (= stock) was defined over time by the water pouring out of the faucet (= flow).

The following examples are taken from Martin (1997).