Q.Classify the following as Stock or Flow, giving one reason each:

A stock is measured at one point of time with no time dimension, while a flow is measured over a period of time; each of these four terms falls clearly into one category once that test is applied. …

The stock/flow test is simple: does the quantity need a date (a stock) or a period (a flow) to make sense?

1. Wealth — Stock. It is meaningful only 'as on' a specific date (e.g., wealth as on 31 March); it has no time-period dimension.
2. Income — Flow. It is meaningful only 'per' a period (income per month, per year); stating income without a time period is meaningless.
3. Population — Stock. The population of a region is stated 'as on' a census date; it is a snapshot number at one point in time. …

Classifying Investment as a stock because it 'adds to capital' — investment is itself the flow variable; Capital is the corresponding stock it adds to. Mixing up a flo …