# ECS-001 Specification

Version 0.1.0 — 18 July 2026

## 1. Status and scope

ECS-001 is an open project specification, not a claim that ETFCTA is an official standards body. It defines how managed-futures ETF classifications are represented, supported, reviewed, and changed.

Normative terms **MUST**, **MUST NOT**, **SHOULD**, and **MAY** indicate requirements.

## Module A — Structural Classification

### 2. Separation of records

A registry implementation MUST keep these entities separate:

1. **Fund** — stable identity and pointers to current decisions.
2. **Source** — a document's identity, authority, dates, locator, and integrity metadata.
3. **Evidence** — a bounded observation from one source, expressed primarily as a summary.
4. **Decision** — the application of one versioned ECS rule to evidence.
5. **Change event** — an event-based record explaining why a published state changed.

### 3. Knowledge states

Structural Fingerprints MUST encode knowledge state, never quality, rank, or score.

| Code | Glyph | Meaning |
|---|---:|---|
| `confirmed_primary` | ● | Confirmed from a primary source |
| `derived_ecs` | ◐ | Derived by applying a named ECS rule |
| `not_disclosed` | ○ | Not disclosed in reviewed evidence |
| `not_applicable` | × | Dimension does not apply |
| `conflicting_evidence` | ! | Reviewed evidence conflicts |

Implementations MUST NOT use filled/empty intensity blocks or aggregate these states into a score.

## Module B — Evidence Sufficiency

### 4. Source identity

A source MUST have a stable ID, type, title, authority, retrieval date, verification status, and locator. Filed documents SHOULD include form and accession number. Immutable documents SHOULD include a SHA-256 hash.

### 5. Quotation policy

- A quotation MUST be verbatim, short, necessary, rights-aware, and paired with an exact locator.
- A quotation MUST NOT be reconstructed from memory or generated from a summary.
- Public evidence SHOULD prefer an original-language summary plus locator and document hash over long quotation storage.
- Absence of a quotation does not weaken evidence when the summary, source identity, and locator are sufficient.

### 6. Evidence admission and sufficiency

Evidence MUST pass the versioned Evidence Admission Protocol before it supports a published decision. Each rule MUST declare its accepted evidence types, minimum number or corroboration requirement, conflict behavior, and review window. Evidence sufficiency is a rule result, not an analyst confidence impression.

### 7. Decisions

Every decision MUST answer:

1. What was classified?
2. Which versioned ECS rule was applied?
3. Which primary evidence supports it?
4. What inference was made?
5. When must it be reviewed again?

A decision MUST identify limitations and MUST NOT silently convert an unknown into a claim. `confirmed` MUST be derived from a passing sufficiency result. A failing or unresolved result MUST produce `provisional`, `needs_review`, or `withdrawn` according to the governing rule.

## Module C — Change and Review Governance

### 8. Change history

History MUST be event-based. Allowed change types are `fund_changed`, `disclosure_changed`, `evidence_improved`, `rule_changed`, and `correction`. A change event MUST distinguish effective time from recording time and MUST identify its trigger and applicable standard version.

### 9. Review governance

Every published decision MUST have a future review date derived from the applicable review-window policy. A new document, conflict, rule migration, announced strategy change, or withdrawal MAY trigger review before that date.

### 10. Correction and withdrawal

Corrections and withdrawals MUST be append-only. They MUST preserve the prior published state, identify the cause, and create a classification change event. A withdrawn record remains addressable and MUST NOT appear as current.

### 11. Admission gate

A real fund MUST NOT enter the public registry until its identity, source set, evidence records, decisions, and cross-references validate. Comparisons MUST NOT be published before relevant dimensions and evidence meet this gate.