Frequency

cultivars.typing.Frequency = Frequency

Alias of Literal['high', 'stock', 'flow'].

How often a variable is seen, and what a low-frequency reading measures.

"high" is observed every sub-period. "stock" is a level read at the end of the low-frequency period – a survey balance, an end-of-quarter position – so the reading is the last sub-period’s value and nothing else. "flow" is accumulated across the period – output, spending, hours – so the reading is a weighted combination of every sub-period in it.

The distinction is not presentational. A stock reading pins down one latent value; a flow reading pins down a weighted sum and leaves the individual sub-periods free to move against each other. Treating a flow as a stock throws away two thirds of a quarterly constraint and silently changes what the model is fitted to.