Evidence

The World Skills Protocol defines Evidence as the foundational, immutable unit of professional truth: a fact produced by an authorized Issuer, cryptographically verifiable by anyone, and separated from trust computation. Evidence is produced; trust is verified. It is append-only, carries full provenance, references a published Framework for its levels, and is the sole input from which a professional's Trust Status is computed.

Canonical Definition

Evidence is an immutable professional fact, produced by an authorized Issuer, that documents the demonstration, observation, or validation of a competency, achievement, or professional event against a referenced Framework, and that can be independently verified through cryptographic integrity and complete provenance, without dependence on the producing Issuer.

Key Facts

  • —Evidence is designed to establish verifiable facts, to preserve historical truth against later reinterpretation, to make verification reproducible by any third party, to support ecosystems with many independent Issuers, and to remain interoperable over long time horizons.
  • —The central design tension is between correction and immutability: real-world attestations contain errors, yet a fact store that permits mutation cannot be trusted.
  • —WSP resolves this in favor of immutability — errors are corrected by emitting new, superseding Evidence, never by altering the record of what was originally attested.
  • —A second tension is between richness and canonicality: Evidence carries only the minimal, canonicalizable payload required to reproduce a verification, deliberately excluding interpretation, presentation, and scoring, all of which belong to other layers.

Why It Exists

Credentials today are custodial: a certificate is trustworthy only while the issuing body survives and remains reachable, and its meaning is entangled with the issuer's branding rather than expressed as a verifiable fact. This produces three failures — credentials die with their issuers, they cannot be recomputed when standards evolve, and they conflate observation with judgment. WSP resolves these by separating the fact from the trust. Evidence is the concept that carries the fact. It exists because the protocol needs an input that is (a) produced by an accountable party, (b) immutable once accepted, (c) independently verifiable without the issuer, and (d) stable across reinterpretation. Without Evidence there is nothing to verify and nothing to recompute; Trust would collapse into reputation, which is precisely the failure WSP is designed to eliminate.

How It Works

An Evidence record is composed of:

  • —an Evidence Identifier (a ULID, prefixed ev_)
  • —a reference to the Professional (Opus ID)
  • —a reference to the Issuer
  • —a Framework Reference and its associated Criterion Levels object
  • —an Observation or Achievement describing what was demonstrated
  • —optional Supporting Artifacts
  • —a Timestamp
  • —a Protocol Version
  • —and Integrity Metadata (the canonicalized digest and its keyed authentication)

An Evidence record is not composed of:

  • —a trust score
  • —a ranking
  • —a level definition
  • —an interpretation
  • —a recommendation
  • —or any presentation layer

Those are produced downstream and are never stored inside Evidence.

The relations are directional. An Issuer produces Evidence. Evidence references a Professional and a Framework coordinate. Opus X ingests Evidence, verifies its integrity, journals it as an Immutable Fact, and creates an Evidence Link to the Passport update. Trust consumes Evidence. No relation permits Evidence to be mutated or deleted after acceptance.

Actors

Evidence is bound to the Professional Passport (OCR-101) through the Evidence Link. It references a Framework coordinate (OCR-115) resolved through the Framework Registry (OCR-119). It is produced by an Issuer (OCR-120), specifically a Certified Issuer (OCR-121). Once accepted it is stored as an Immutable Fact (OCR-114) and characterized by Evidence Integrity (OCR-113) and Evidence Source provenance (OCR-111). It is the sole input to Trust (OCR-105) and Trust Status (OCR-106), and it is what a Verification (OCR-107) inspects when answering a Verification Request (OCR-108) with a Verification Response (OCR-109). It belongs to the World Skills Protocol (OCR-100).

Lifecycle

  1. 01Observation — a professional demonstration is performed and observed by an authorized Issuer.
  2. 02Creation — the Issuer assembles the Evidence payload, including the Framework Reference and Criterion Levels object.
  3. 03Authentication — integrity metadata is computed over the JCS-canonicalized payload.
  4. 04Submission — the Evidence is submitted to Opus X.
  5. 05Ingestion & Verification — Opus X recomputes the JCS digest, verifies integrity in constant time, and validates provenance and Issuer authorization.
  6. 06Acceptance — the Evidence is journaled as an append-only Immutable Fact; an Evidence Link to the resulting Passport update is created.
  7. 07Verifiability — the fact supports future, reproducible verification by any third party, independent of the Issuer.
  8. 08Supersession (optional) — a later Evidence may supersede the interpretation of an earlier one; the earlier fact is preserved.
  9. 09Revocation (optional) — an accepted Evidence may be revoked by a superseding revocation fact; the original record is preserved and marked revoked.

Examples

  • ·A trading academy (Certified Issuer) observes a demonstrated risk-management competency and emits Evidence referencing wtr:212 with criterion_levels for S03.C08, S08.C06, S05.C08, and S02.C12; Opus X verifies, journals the fact, and links it to the Passport.
  • ·A university emits Evidence attesting a completed degree; the fact is later reinterpreted under a new Framework version, and Trust is recomputed without altering the original Evidence.
  • ·An employer emits Evidence of workplace performance; a correction is required, so a new superseding Evidence is emitted and the original is preserved.
  • ·A professional association revokes a lapsed certification by journaling a revocation fact; the original Evidence remains, marked revoked.

Counter Examples

  • ×A reputation score computed from many facts — that is Trust Status (OCR-106), not Evidence.
  • ×A self-declared skill entered by the professional — Evidence MUST be produced by an authorized Issuer.
  • ×A recommendation letter expressing opinion — Evidence carries facts, not opinions.
  • ×A level definition ("level 3 means…") — levels belong to the Framework, not to Evidence.
  • ×A Verification Response asserting "verified" — that is the output of inspecting Evidence, not Evidence itself.

Distinctions

Evidence is often mistaken for a credential or a badge; it is neither — it is the underlying fact from which presentations are derived. It is mistaken for a score; it never carries one. It is assumed mutable ("just fix the record"); it is append-only, and corrections are new facts. It is assumed to define levels; it references levels defined by the Framework. It is assumed to depend on the Issuer at verification time; independent verifiability is its defining property.

FAQ

What is Evidence?
An immutable, independently verifiable professional fact produced by an authorized Issuer.
Who produces Evidence?
A Certified Issuer. Never Opus X, never the professional, never an AI.
Can Evidence be modified?
No. It is append-only once accepted.
How are errors corrected?
By emitting a new superseding Evidence; the original is preserved.
Can Evidence be deleted?
No. Withdrawals are expressed as revocation facts.
Does Evidence contain a trust score?
No. Trust is computed downstream from Evidence.
Where are levels defined?
In the Framework, published by Opus X — not inside Evidence.
How is Criterion Levels represented?
As an object keyed by criterion, e.g. { "S03.C08": <level> }.
Why an object and not an array?
To preserve the criterion→level binding unambiguously.
What is the type field for?
It is the discriminator, placed as a sibling of the body for routing.
How is integrity computed?
Over the JCS-canonicalized (RFC 8785) payload.
How is integrity verified?
By recomputing the digest and comparing in constant time.
What identifier does Evidence use?
A ULID prefixed ev_.
Is Evidence verifiable without the Issuer?
Yes. Independent verifiability is required.
What binds Evidence to a Passport?
A uniqueness-constrained Evidence Link.
Can one Evidence link to many Passport updates?
No. The link enforces one-to-one uniqueness.
What happens when a Framework is reinterpreted?
Trust is recomputed; Evidence is not rewritten.
Can an AI generate Evidence?
No. An AI may read it, never fabricate it.
Can a superseded Evidence be shown as current?
No. Provenance and status MUST be preserved.
Does consent deletion remove Evidence?
No. Consent governs disclosure, not existence.
What is the difference between Evidence and an Immutable Fact?
Evidence is the concept; the Immutable Fact is its accepted, journaled record (OCR-114).
Can Evidence reference multiple criteria?
Yes, within a Framework coordinate.
Is a rejected submission stored as Evidence?
No. Rejection is terminal and journals no fact.

Related Entities

Normative Sources

OCR-100 World Skills Protocol · OCR-101 Professional Passport · OCR-103 Professional · OCR-104 Opus ID · OCR-105 Trust · OCR-106 Trust Status · OCR-107 Verification · OCR-108 Verification Request · OCR-109 Verification Response · OCR-111 Evidence Source · OCR-112 Evidence Lifecycle · OCR-113 Evidence Integrity · OCR-114 Immutable Fact · OCR-115 Framework · OCR-119 Framework Registry · OCR-120 Issuer · OCR-121 Certified Issuer.

View the Evidence Registry Entry