# Assumption Mapping

> Document and prioritize the assumptions underlying your product strategy before validation.

- Skill: `sethdford/assumption-mapping` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add sethdford/assumption-mapping`
- Raw SKILL.md: https://api.skillmd.com/api/skills/sethdford/assumption-mapping/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Product & Planning, Coding & Dev Tools
- Author: sethdford (https://skillmd.com/u/sethdford)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/sethdford/assumption-mapping

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# Assumption Mapping

Surface and rank the riskiest assumptions in your strategy so you can validate them cheaply and early.

## Context

You are identifying what must be true for a product to succeed. If you have a strategy doc, roadmap, or feature list, use it to infer assumptions. Your goal is to list them, prioritize by risk, and design quick tests.

## Domain Context

- **Lean Startup (Eric Ries)**: Test riskiest assumptions first
- **Jobs-to-be-Done**: Validate the job, not the feature
- **Leap-of-faith assumptions (Steve Blank)**: What would make this fail?
- **Assumption hierarchy**: Market > Customer > Product > Business

## Instructions

1. **List all assumptions**: Write out every assumption your strategy depends on
2. **Categorize by type**: Market, customer behavior, product, business
3. **Rank by risk**: Which would tank the entire strategy if false?
4. **Design cheap tests**: For high-risk assumptions, sketch tests <1 week, <$5K
5. **Identify dependencies**: Which assumptions must validate first?
6. **Plan sequence**: Validate in dependency order, riskiest first

## Output Artifact

Assumption mapping (2-3 pages):
- List of all assumptions (50-100 per product)
- Risk ranking (color-coded)
- Validation test for high-risk assumptions
- Success criteria for each
- Estimated cost/timeline

## Anti-Patterns

- **Assuming customer wants your solution**: Validating the solution, not the problem
- **Treating all assumptions equally**: Not triaging which failures would kill strategy
- **Expensive validation**: 6 months research before prototyping
- **No success criteria**: "We'll talk to customers and see" vs. clear threshold

## Further Reading

- *The Lean Startup* (Eric Ries) — assumption-driven development
- *Running Lean* (Ash Maurya) — lean canvas
- *Empowered* (Marty Cagan, Chris Jones) — discovery loops