Size a market from the bottom up

Size the market for {{product}} sold to {{customer type}} in {{geography}}.

Build it bottom-up, not from an analyst's TAM number:
1. Define the unit of demand precisely (a company? a seat? a transaction?).
2. Count the population from sources you can cite — census, industry registries, platform counts, employment data. Show the arithmetic at each step.
3. Apply qualification filters one at a time, each with a cited or clearly-labelled assumed rate: who has the problem, who knows it, who can buy, who can be reached.
4. Price it at our realistic ACV, not aspirational.
5. Then do a top-down cross-check from any published market figure and reconcile the gap. Explain which you trust and why.
6. Sensitivity: show how the answer moves if each assumption is half or double.
7. List every number that is an assumption rather than a source, in one place.

Cite URLs. Never present an assumed rate as data.