/tam-sam-som-calculator

name: tam-sam-som-calculator
argument-hint: "[product idea] [market constraints]"
description: Calculate TAM, SAM, and SOM with explicit assumptions, methods, and caveats. Use when sizing a market for a product idea, business case, or executive review.
intent: >-
  Guide product managers through calculating Total Addressable Market (TAM), Serviceable Available Market (SAM), and Serviceable Obtainable Market (SOM) for a product idea by asking adaptive, contextually relevant questions. Use this to build defensible market size estimates backed by real-world citations, economic projections, and population data—essential for pitching to investors, securing budget, or validating product-market fit.
type: interactive
theme: market-intelligence
best_for:
  - "Sizing a market for a business case an executive will question"
  - "Making your market assumptions explicit and attackable"
  - "Replacing a top-down guess with a defensible bottom-up estimate"
scenarios:
  - "I need market sizing for a business case our CFO will pick apart"
  - "Our TAM number came from a slide nobody can source — rebuild it properly"
estimated_time: "20-40 min"

Purpose

Guide product managers through calculating Total Addressable Market (TAM), Serviceable Available Market (SAM), and Serviceable Obtainable Market (SOM) for a product idea by asking adaptive, contextually relevant questions. Use this to build defensible market size estimates backed by real-world citations, economic projections, and population data—essential for pitching to investors, securing budget, or validating product-market fit.

This is not a back-of-napkin guess—it's a structured, citation-backed analysis that withstands scrutiny.

Input

**Works best with:** The product or idea being sized, and any market constraints you already know (geography, vertical, customer type). **Also useful:** Pricing assumptions, comparable companies, and the audience for the numbers (investors, execs, business case).

Anything supplied with the invocation itself — text after the skill name, a pasted context dump, or an appended `ARGUMENTS:` line — counts as answers already given. Use it and skip whatever it covers; don't re-ask.

**Arriving empty-handed? That works too.** The calculator opens by asking what you're sizing and for whom, then works through method and assumptions.

**Three entry modes** — pick whichever matches where your evidence lives: 1. **Bring your own numbers** — you have population and ARPU figures; jump to the math (the helper script makes this deterministic) 2. **Guided interview** — up to 4 adaptive questions build the inputs with you (the default flow below) 3. **Autonomous research** — the agent builds a bottom-up, citation-backed estimate from government statistics and filings while you review the evidence (see *Mode 3* in Application)

**Example invocation:** `Size the market: AI scheduling assistant for independent dental practices, US only, $99/mo price point.` — or for research mode: `Research-mode market sizing: field-service dispatch software, DACH region; I have no numbers yet.`

Key Concepts

TAM/SAM/SOM Framework

The three-tier market sizing model:

**Total Addressable Market (TAM):**

• The total market demand for a product or service
• "If we captured 100% of the market, what's the revenue?"
• Broadest possible market (no constraints)

**Serviceable Available Market (SAM):**

• The segment of TAM your company can realistically target
• Narrowed by geography, firmographics, demographics, or product constraints
• "Who can we actually reach with our product?"

**Serviceable Obtainable Market (SOM):**

• The portion of SAM you can realistically capture
• Accounts for competition, market constraints, go-to-market capacity
• "What can we capture in the next 1-3 years?"

Why This Works

• **Top-down validation:** TAM → SAM → SOM ensures estimates are grounded in reality
• **Investor-friendly:** Standard framework VCs and execs understand
• **Citation-backed:** Real data sources (Census, Statista, World Bank) add credibility
• **Adaptive:** Questions adjust based on context (B2B vs. B2C, US vs. global, etc.)

Anti-Patterns (What This Is NOT)

• **Not a single-number guess:** "The market is $10B" without supporting data
• **Not static:** Markets evolve—reassess annually
• **Not a substitute for customer validation:** Market size ≠ product-market fit

When to Use This

• Pitching to investors or execs (need market size in deck)
• Validating product ideas (is the market big enough?)
• Prioritizing product lines (which has bigger opportunity?)
• Setting growth targets (what's realistic to capture?)

When NOT to Use This

• For internal tools with captive users (no external market)
• Before defining the problem (market sizing requires clear problem space)
• As the only validation (pair with customer research)

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Facilitation Source of Truth

Use [`workshop-facilitation`](../workshop-facilitation/SKILL.md) as the default interaction protocol for this skill.

It defines:

• session heads-up + entry mode (Guided, Context dump, Best guess)
• one-question turns with plain-language prompts
• progress labels (for example, Context Qx/8 and Scoring Qx/5)
• interruption handling and pause/resume behavior
• numbered recommendations at decision points
• quick-select numbered response options for regular questions (include `Other (specify)` when useful)

This file defines the domain-specific assessment content. If there is a conflict, follow this file's domain logic.

Application

Use `template.md` for the full fill-in structure.

This interactive skill asks **up to 4 adaptive questions**, offering **enumerated context-aware options** at each step. The agent adapts questions based on previous responses.

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Step 0: Gather Context (Before Questions)

**Agent suggests:**

Before we begin, it's helpful to have product context. If available, please share:

**For Your Own Product:**

• Website copy (homepage, product pa