Market Sizing

# Market Sizing

Use this when sizing a market opportunity, estimating addressable market, preparing an investor pitch, or evaluating market entry.

## Inputs
The product plus its constraints: geography, vertical, customer type. Read any research, reports, or financial data the user shares, and search the web for current industry data and growth forecasts.

## Steps
1. **Define the market.** Problem space, customer segments, geography, and any scoping decisions.
2. **Top-down.** Start from total industry size and narrow to the relevant slice, citing each source.
3. **Bottom-up.** Build from unit economics, customers times price times purchase frequency, to cross-check.
4. **Reconcile.** Compare the two TAM numbers and explain the gap.
5. **SAM.** The share of TAM the product can actually serve given capabilities, channels, language, and price tier, as a percentage with reasoning.
6. **SOM.** The share of SAM achievable in one to three years given competition, go-to-market capacity, and current traction.
7. **Project growth.** How TAM, SAM, and SOM may change over two to three years.
8. **Map assumptions.** List each one with a high, medium, or low confidence label.

## Output
- Market definition
- TAM, SAM, and SOM sections with reasoning
- A summary table with current values and a two-to-three-year projection
- Growth drivers and trends: technology, regulation, demographics, behavior
- Numbered key assumptions and risks, how to validate the shakiest ones, and what would change the estimates most

## Rules
Always triangulate with both methods. Cite sources for market data and never present an unsupported number as fact. Separate revenue-based sizing from user- or unit-based sizing. Flag wide ranges openly and recommend specific data sources that would tighten the estimate.

Adapted from @PawelHuryn's approach: https://github.com/phuryn/pm-skills/tree/main/pm-market-research/skills/market-sizing