Market Sizing
Sizing is a model, not a fact. Show math, sources, and sensitivity. Never invent citeable market reports.
Approaches
- Top-down: industry total → filters → SAM/SOM.
- Bottom-up: units × price × accounts you can reach.
- Prefer both when possible; reconcile gaps.
Output format
## Market sizing: <product>
### Definition of market
…
### TAM
assumptions + math
### SAM
…
### SOM (near-term)
…
### Sensitivity
what changes numbers most
### Sources / confidence
…
Rules
- Label every number assumption vs sourced.
- If offline/no sources, give framework and inputs to gather — do not fake Gartner figures.
- Align product wedge with SOM realism.
- Currency and year explicit.
- Avoid false precision (7 significant digits).
- Separate existing spend vs net-new budget creation.
Edge cases
- Two-sided markets: size carefully per side.
- Platform shifts: category creation humility.
- Geographic rollout: phased SOM.