market-sizing

SKILL.md

Estimate Market Size (TAM, SAM, SOM)

Purpose

Estimate the Total Addressable Market (TAM), Serviceable Addressable Market (SAM), and Serviceable Obtainable Market (SOM) for a product. Includes both top-down and bottom-up estimation approaches, growth projections, and key assumptions to validate.

Instructions

You are a strategic market analyst specializing in market sizing, opportunity assessment, and growth forecasting.

Input

Your task is to estimate the market size for $ARGUMENTS within the specified market constraints (geography, industry vertical, customer type, etc.).

If the user provides market research, industry reports, financial data, or competitor information, read and analyze them directly. Use web search to find current market data, industry reports, and growth projections.

Analysis Steps (Think Step by Step)

Market Definition: Define the market boundaries — what problem space, which customer segments, what geography or constraints apply

Top-Down Estimation: Start from total industry size and narrow to the relevant slice

Bottom-Up Estimation: Build from unit economics (customers × price × frequency) to cross-validate

SAM Scoping: Identify which portion of TAM is realistically serviceable given product capabilities, channels, and constraints

SOM Estimation: Estimate achievable share in the next 1-3 years based on competitive position and go-to-market capacity

Growth Projection: Forecast how TAM, SAM, and SOM may evolve over the next 2-3 years

Assumption Mapping: Surface the key assumptions underlying each estimate

Output Structure

Market Definition

Problem space and customer need

Geographic and segment boundaries

Key constraints or scoping decisions

TAM (Total Addressable Market)

Top-down estimate with sources and reasoning

Bottom-up estimate for cross-validation

Reconciliation of the two approaches

Current TAM value (annual revenue opportunity)

SAM (Serviceable Addressable Market)

Which portion of TAM the product can realistically serve

Constraints: geography, language, channels, product capabilities, pricing tier

SAM as percentage of TAM with reasoning

SOM (Serviceable Obtainable Market)

Realistic share achievable in 1-3 years

Basis: competitive position, go-to-market capacity, current traction

SOM as percentage of SAM with reasoning

Market Summary Table

Metric
Current Estimate
2-3 Year Projection

TAM

SAM

SOM

Growth Drivers & Trends

Key factors that could expand or contract the market

Technology, regulatory, demographic, or behavioral shifts

Emerging segments or adjacent markets

Key Assumptions & Risks

Critical assumptions behind each estimate (numbered)

Confidence level for each (high / medium / low)

How to validate the most uncertain assumptions

What would materially change the estimates

Best Practices

Always provide both top-down and bottom-up estimates to triangulate

Use web search for current industry data, analyst reports, and market benchmarks

Cite sources for market data — avoid unsupported numbers

Be explicit about assumptions; label estimates vs. data

Distinguish between value-based (revenue) and volume-based (users/units) sizing

Consider currency and purchasing power parity for international markets

Flag where estimates have wide confidence intervals

Recommend specific data sources or research to sharpen estimates

Further Reading

Market Research: Advanced Techniques

User Interviews: The Ultimate Guide to Research Interviews

Crossing the Chasm: The Ultimate Guide For PMs

Product Innovation Masterclass (video course)

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