Module 11: System Failure Analysis
1. Definition (from Module 1)
A System Failure exists when a rule is too complex for a standard POS or a consumer to verify at transaction time, so wrong tax or no tax is collected by default.
2. Ambiguity points (non-exhaustive)
| Domain | Why standard POS fails |
|---|---|
| Construction / fixtures | Module 7 — line items need legal fixture vs. realty classification; SKU text won't resolve it. |
| Enumerated services | Module 4 — $5,000 thresholds, EIS vs. professional services, bundled labor. |
| Food & beverage | Module 2 — off-premises vs. on-premises, soft drink tests. |
| Use tax | Module 5 — no receipt when remote seller doesn't collect; POS has nothing to show. |
| Marketplace | Module 8 — facilitator vs. seller and wrong tax code on long-tail SKUs. |
3. Pattern: law vs. operational reality
Statute may be knowable to a specialist; Operational Reality is millions of untrained cashiers and automated carts. Ambiguity + volume = leakage at scale.
4. Analytical lenses (apply to every module)
Use these tests consistently when reviewing a rule or receipt:
A. Determinism test
Can two different parties reach the same tax outcome using only the law and stated facts?
If not → system failure.
B. Replicability test
Can a transaction be classified identically across:
- Different businesses
- Different auditors
- Different POS systems
If not → inconsistency risk and unfair competition.
C. Binary classification requirement
Every transaction should resolve to TAXABLE or NOT TAXABLE before rate lookup. Subjective “it depends on the auditor” layers belong in audit dispute, not at checkout.
5. Input to reform
Module 12 converts this map into a Real-Time Validation mandate: shared signals, authoritative taxability answers, and transaction-level proof where flat rate tables are insufficient.
Outcomes
- [x] Rank ambiguity points by domain (Modules 2–8 table above)
- [ ] Estimated $ ranking per domain (tie to Module 13 modeling)
- [ ] POS capability survey: metadata (NAICS, job type, contract flag) that could feed rules
- [ ] Interagency data concepts: building permits ↔ fixture purchases