Classification Methodology
Framework version: fv_002 (Frozen)
Overview
The Sovereign Classification Engine employs a deterministic, two-output classification model. Every coin in the universe receives both a Scarcity Rating and a Recognition Status, computed independently from verified evidence. The framework is frozen — no modifications to thresholds, pathways, or benchmark definitions are permitted without formal governance review.
Output 1: Scarcity Rating
The Scarcity Rating reflects how difficult a coin is to obtain, based on how many were produced and how many are believed to survive. It is derived from two inputs:
Production Estimate (PE)
The PE band is determined by the coin's verified mintage figure and its issue type. Different thresholds apply to Circulation and Proof issues, reflecting the fundamentally different production contexts.
Circulation Thresholds
| Band | Mintage Range |
|---|---|
| Common | > 100,000 |
| Scarce | 10,001 – 100,000 |
| Rare | 1,001 – 10,000 |
| Very Rare | ≤ 1,000 |
Proof Thresholds
| Band | Mintage Range |
|---|---|
| Common | > 15,000 |
| Scarce | 5,001 – 15,000 |
| Rare | 926 – 5,000 |
| Very Rare | ≤ 925 |
Note: Extreme Rarity cannot be achieved through PE alone. It is only assigned when Survival Evidence indicates significantly fewer survivors than production would suggest.
Survival Evidence (SE)
The SE input captures independent evidence about actual survival rates, primarily drawn from Marsh rarity ratings. SE can override PE, but only in the more restrictive direction — it can never reduce a coin's scarcity rating below what PE alone would assign.
| Marsh Rating | SCE SE Band |
|---|---|
| C | Common |
| S | Scarce |
| R | Rare |
| R2, R3 | Very Rare |
| R4, R5, R6, R7 | Extreme Rarity |
Final Scarcity Rating
The final Scarcity Rating is the more restrictive of PE and SE. If SE indicates greater rarity than PE, SE overrides. If PE is already more restrictive than SE (or if no SE data exists), PE stands alone.
Output 2: Recognition Status
The Recognition Status captures whether a coin is acknowledged as numismatically significant beyond its basic date-mint identity. It is determined by documented evidence from authoritative references.
Status Tiers
| Status | Qualifying Evidence |
|---|---|
| Key Date | Pathway 1: Explicitly identified as a key date in two or more authoritative references Pathway 2: Inaugural series type debut (first coin of a new series) |
| Recognised Type | Included in a registry set OR identified as a distinct type in two or more references |
| Catalogued Variation | Documented as a distinct structural variation (die variety, design subtype) |
| Standard Issue | Default — no qualifying evidence for a higher status |
Provenance
Every classification includes a complete provenance record documenting:
- The PE driver (mintage figure and threshold set applied)
- The SE driver (Marsh rating and override decision)
- The recognition pathway (which evidence qualified the status)
- The framework version under which the classification was computed
- Timestamp of the classification decision
Benchmark Guard
Nine benchmark coins are permanently locked under fv_002. These coins span the full range of scarcity ratings and recognition statuses, and their expected classifications are validated on every build. If any benchmark fails validation, the build is rejected and no changes are deployed.
Framework Governance
The fv_002 framework is frozen. This means:
- PE thresholds cannot be modified
- SE mapping cannot be altered
- Recognition pathways cannot be changed
- Benchmark expected values cannot be updated
- New coins may be added to the universe, but existing classifications are immutable
Any proposed change to the framework requires a formal governance review, a new framework version number, and re-validation of all benchmarks under the new rules.