OPDA Knowledge base
Concept tier claim

Evidence

opda:Evidence

Evidence

Evidence is the supporting artefact behind a Claim. OPDA recognises three deliberately-distinct kinds of evidence — Document, Electronic Record, and Vouch — and explicitly does not collapse them, because they carry different lifecycles, different verification mechanics, and different assurance ceilings.

Why it matters

The three subtypes correspond to the OIDC4IDA and eIDAS evidence categories. A Document Evidence (e.g. grant of probate) lives on paper or in a scan with a HMCTS issuance chain; an Electronic Record Evidence lives in a structured API response from an authoritative source; a Vouch Evidence is a regulated professional’s attestation. They are qualitatively different — and treating them uniformly hides the data downstream consumers need to make verification decisions.

If you are an integrator surfacing evidence to a verification activity, this is the supertype whose subtype dispatch you need.

Hard cases

  • Subtype confusion. A scanned paper Document recorded as an Electronic Record. The IC discriminates by source provenance, not by digital format — a scanned paper artefact is still Document Evidence.
  • Mixed evidence chain. One Claim supported by a Document, an Electronic Record, and a Vouch in combination. The three coexist as distinct Evidence instances; no collapse.
  • Evidence withdrawn. A Document is invalidated post-hoc (e.g. probate revoked). The Evidence record persists with a withdrawal annotation; downstream Verification Activities that relied on it inherit a status change.

Identity Criterion

An Evidence record is identified by its (subtype, source-authority record-id) pair. Two records refer to the same Evidence only if both components match. See the Logical tier → for the typed structure and the subtype-dispatching SHACL shape.

%%{init: {"theme": "base"}}%% flowchart LR accTitle: Evidence related-Kinds neighbourhood graph accDescr: Evidence as the supertype of three deliberately-distinct subtypes — Document, Electronic Record, Vouch — each with its own provenance chain and assurance ceiling; supports Claims and is used by Verification Activities. classDef centre fill:#E1BEE7,stroke:#6A1B9A,stroke-width:3px,color:#4A148C classDef cls fill:#B3E5FC,stroke:#0277BD,stroke-width:2px,color:#01579B Evidence["Evidence
(supertype)"]:::centre DocEv["DocumentEvidence
(HMCTS, etc.)"]:::cls ERecEv["ElectronicRecordEvidence
(HMRC API, etc.)"]:::cls VouchEv["VouchEvidence
(SRA-licensed)"]:::cls Claim["Claim"]:::cls Verification["VerificationActivity"]:::cls Evidence --> DocEv Evidence --> ERecEv Evidence --> VouchEv Claim -->|"supportedBy"| Evidence Verification -->|"uses"| Evidence

Source ODR

ODR-0009 — Claims, evidence, provenance §Q1

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