Step 1
Serviceable value equals eligible accounts multiplied by expected annual contract value.
Public tool method · Version 1.0.0
Bottom-Up TAM Builder
Use this method when you need to answer: What serviceable market can we defend from buyer groups and economics? It turns the evidence you supply into a Bottom-up market model by applying explicit, versioned decision rules. The result is not a benchmark or certification. It shows the strongest evidence, riskiest input, next action, owner, and review date so another reader can inspect and challenge the decision.
Last material review 2026-08-08 · Next review 2027-02-04
Question answered
What serviceable market can we defend from buyer groups and economics?
The model uses counted accounts, serviceability, buyer, trigger, contract range, source, and confidence instead of a top-down industry percentage.
Step 2
Eligible accounts equal counted accounts multiplied by the serviceable percentage.
Step 3
Confidence-adjusted value equals serviceable value multiplied by evidence confidence.
Step 4
Raw and confidence-adjusted ranges are shown separately.
Step 5
Record the required inputs and label missing or estimated evidence before classification.
Assumptions and limits
- A confidence-adjusted range is not verified market size or probability.
Usefulness hypothesis
A segment model improves investor and operating challenges to market-size claims.
Primary metric: Segment-table export or TAM workshop pre-read
Worked example and modes
The same method, preserved entry intent.
- Segment
- US professional firms with 100 to 1000 staff
- Account Count
- 1800
- Eligibility
- 35
- Buyer
- Chief operating or risk officer
- Trigger
- Client-facing AI workflow moves from pilot to controlled use
- Contract Low
- 40000
Distribution package
Use, embed, and share the instrument.
Blank CSV template90-second demonstrationThree share treatmentsPlain-language answer
Embed with canonical attribution
<iframe src="https://petrichorgrowth.com/tools/tam-lie-detector/embed.html" title="Bottom-Up TAM Builder" loading="lazy" width="100%" height="900"></iframe>
<p>Source: <a href="https://petrichorgrowth.com/tools/tam-lie-detector">Bottom-Up TAM Builder by Petrichor</a></p>Ownership and change control
Who keeps the result defensible?
Product
Petrichor product
Method
Petrichor strategy
Evidence
Petrichor research
Privacy
Petrichor operations
Security
Petrichor web platform
Distribution
Petrichor growth
Support
Petrichor client experience
A material method change requires a reason, impact note, fixture rerun, semantic-version increment, and public entry in the method change log.
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AI Skill Assurance and Deployment Readiness
Determine whether a bounded AI workflow has the evidence and controls required for qualified review.
Related plain-language answers
Spend-at-Risk Calculator answerReach Reality answerAI Skill Assurance answer
Method questions
What another reader should know.
What does the Bottom-Up TAM Builder method produce?
A versioned Bottom-up market model with visible reasoning, evidence status, next action, ownership, and review date.
What inputs does Bottom-Up TAM Builder require?
Only the structured decision evidence named by the instrument. Missing or estimated inputs remain visible in the result.
Does the method use AI or a cross-customer benchmark?
No. It applies deterministic rules to the user's inputs and does not compare one customer with another.
When is the method reviewed or changed?
The current method is reviewed at least every 180 days. Material changes require new fixtures, a version increment, and a public change note.
When should the artifact move into facilitated work?
When the unresolved decision requires team challenge, evidence reconciliation, dissent, ownership, and an organizational commitment.