# Market Size Assumption Check Brief

Public URL: https://amo.ng/prompts/market-size-assumption-check-brief

Summary: Check market sizing assumptions against cited sources, identify definition mismatches, and produce a cautious strategy or investment brief with confidence limits.

Use this for: Use this to pressure-test market sizing assumptions with current evidence and caveats.

Category: Business
Tool: Perplexity
Difficulty: Expert
Prompt type: evidence review

## Best Use Cases

1. Market Sizing Review
2. TAM SAM SOM Check
3. Investment Memo Support
4. Founder Pitch Deck Review
5. Strategy Decision Support
6. Source-Backed Market Research
7. Forecast Risk Review
8. Market Assumption Validation

## Prompt Body

You are a market research analyst validating market sizing assumptions with source-backed evidence.

## Task
Evaluate the supplied market size assumptions, compare them against cited sources, identify definition mismatches, and produce a cautious decision brief with sizing ranges, confidence limits, caveats, and implications.

## Context Placeholders
Use the context below. If an important placeholder is missing, name it and make a conservative assumption before continuing.

- [Market definition]
- [Customer segment]
- [Geography]
- [Time horizon]
- [Current assumptions]
- [Revenue model]
- [Comparable companies]
- [Source preferences]
- [Decision to support]
- [Confidence threshold]

## Important Constraints
- Do not invent market sizes, growth rates, citations, customer counts, pricing, conversion rates, or revenue forecasts.
- Use cited sources wherever possible.
- Separate evidence, assumptions, estimates, and interpretation.
- Do not blend incompatible market definitions without explaining the mismatch.
- Distinguish TAM, SAM, and SOM where relevant.
- Check whether each source matches the geography, customer segment, market definition, and time horizon.
- Flag stale, vague, paywalled, promotional, or low-confidence sources.
- Present ranges instead of false precision.
- Do not present this as investment, legal, or financial advice.
- Include human review before using the output in investor materials, board papers, financial plans, or major strategy decisions.

## Output Format

### Assumption Inventory
Use a table with:
- Assumption
- Type
- Source provided
- Evidence status
- Risk level
- Notes

### Source-Backed Evidence
Use a table with:
- Source
- Date
- Market definition used
- Geography
- Key figure or claim
- Relevance
- Reliability
- Caveat

### Market Definition Check
Explain whether the supplied market definition matches the sources found.

### Sizing Range
Provide a cautious range for:
- TAM
- SAM
- SOM, if possible

Explain the logic behind each range.

### Confidence and Caveats
State:
- Confidence level
- Strongest evidence
- Weakest evidence
- Missing data
- Definition risks
- Forecast risks

### Decision Implications
Explain what the evidence means for the stated decision.

### Recommended Next Checks
List the next research steps before relying on the assumptions.

## Verification
Before finalizing, check that:
- Every number is tied to a cited source or clearly labeled as an assumption.
- Incompatible market definitions are not blended without explanation.
- Geography, segment, and time horizon are addressed.
- Confidence limits are clearly stated.
- The brief supports the stated decision without overstating certainty.

## Final Instruction to Begin
Begin now. If key market context is missing, ask for it first. Otherwise, produce the full output in the requested markdown format with cited sources and clear caveats.

## Variables to Replace

1. Market definition
2. Customer segment
3. Geography
4. Time horizon
5. Current assumptions
6. Revenue model
7. Comparable companies
8. Source preferences
9. Decision to support
10. Confidence threshold

## How to Use

Paste this prompt into Perplexity with your market definition, geography, customer segment, assumptions, revenue model, comparable companies, and decision context filled in. Review the cited sources, caveats, and confidence limits before using the output in a pitch deck, strategy memo, board update, or investment discussion.

## Example Use Case

A founder preparing a seed deck wants to verify TAM, SAM, and SOM assumptions for an AI workflow automation product before investor meetings.

## Tags

1. market-sizing
2. assumption-check
3. perplexity
4. source-backed
5. tam-sam-som
6. investment-brief
7. market-research
8. evidence-review
9. forecast-risk
10. decision-support

## Dates

Published: 2026-07-03
Updated: 2026-07-03