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P194 — AIEP — Evidence Currency and Corroboration Protocol

Publication Date: 2026-03-27 Status: Open Source Prior Art Disclosure Licence: Apache License 2.0 Author/Organisation: Phatfella Ltd Schema: AIEP_OS_SPEC_TEMPLATE v1.0.1 — https://aiep.dev/schemas/aiep-os-spec-template/v1.0.1

Framework Context

[0001] This disclosure operates within an Architected Instruction and Evidence Protocol (AIEP) environment as defined in United Kingdom patent application number GB2519711.2, filed 20 November 2025, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure defines a protocol for computing a unified EvidenceCurrencyScore — a joint measure of both the temporal currency and the corroborative strength of an evidence artefact or evidence set — enabling reasoning chains to identify evidence that is simultaneously fresh and corroborated, distinct from evidence that is fresh but uncorroborated, or corroborated but stale.

Field of the Disclosure

[0003] This disclosure relates to composite evidence quality scoring combining temporal freshness and corroboration dimensions in artificial intelligence evidence systems.

[0004] More particularly, the disclosure concerns: an EvidenceCurrencyScore schema; the interaction between freshness decay (P147) and corroboration scoring (P184); currency decay bands; currency score computation; corpus-level currency distribution reporting; and integration with reasoning-ready packages (P174) and aggregate scoring (P186).

Background

[0005] Freshness scores (P147) measure how recently an artefact was published relative to the current date. Corroboration scores (P184) measure how many independent sources agree with the artefact’s claim. These two dimensions are orthogonal: an artefact may be stale but highly corroborated (a 10-year-old finding replicated by dozens of subsequent studies); or fresh but uncorroborated (a brand-new preprint with no independent verification).

[0006] For reasoning chains, the most reliable evidence is evidence that is both fresh (observationally current) and corroborated (independently supported). A combined EvidenceCurrencyScore captures this joint quality in a single value that a reasoning chain can interpret as the overall epistemic currency of an artefact — how confident can reasoning be that the claim is both current and multiply supported.

Summary of the Disclosure

[0007] EvidenceCurrencyScore Schema:

currency_record_id — SHA-256 of canonical serialisation
subject_deid — DEID (P162)
freshness_score — current freshness score (P147), value in [0.0, 1.0]
corroboration_score — current corroboration score (P184), value in [0.0, 1.0]
currency_score — computed composite (see [0008])
currency_band — CURRENT_AND_CORROBORATED (currency ≥ 0.7), CURRENT_UNCORROBORATED (freshness ≥ 0.7, corroboration < 0.3), STALE_CORROBORATED (freshness < 0.4, corroboration ≥ 0.7), STALE_UNCORROBORATED (both < 0.4), MODERATE (all other combinations)
computed_at — ISO 8601 timestamp

[0008] EvidenceCurrencyScore Computation: The currency score is computed as: currency_score = geometric_mean(freshness_score, corroboration_score) = sqrt(freshness_score × corroboration_score)

The geometric mean is used because it penalises extreme imbalance more than an arithmetic mean: an artefact with freshness = 1.0 and corroboration = 0.0 scores 0.0 (uncorroborated evidence has zero currency regardless of freshness); an artefact with freshness = 0.7 and corroboration = 0.7 scores 0.7 (balanced moderate quality).

[0009] Currency Bands: The currency_band provides a semantic classification:

CURRENT_AND_CORROBORATED — currency_score ≥ 0.7; the evidence is both fresh and multiply supported; highest reliability for reasoning
CURRENT_UNCORROBORATED — freshness ≥ 0.7 but corroboration < 0.3; recent but not independently confirmed; treat as preliminary evidence
STALE_CORROBORATED — freshness < 0.4 but corroboration ≥ 0.7; older finding with strong independent support; may be superseded but foundationally solid
STALE_UNCORROBORATED — both dimensions low; lowest reliability; reasoning chains should seek better evidence before drawing conclusions
MODERATE — all other combinations; moderate confidence; per-artefact evaluation required

[0010] Currency Score Update Triggers: EvidenceCurrencyScore is recomputed whenever either the underlying freshness_score or corroboration_score for the artefact changes (as governed by each protocol’s own update triggers — P147 freshness decay and P184 corroboration update events).

[0011] Corpus Currency Distribution: The CurrencyDistributionReport is published daily as part of the Evidence Quality Metrics corpus health report (P172), giving operators visibility into the proportion of the corpus in each currency band. A corpus where the majority of artefacts are in STALE_UNCORROBORATED requires urgent evidence refresh.

[0012] Currency Score in Evidence Packages: The EvidencePackageItem (P174) includes currency_score and currency_band alongside trust_score, freshness_score, and corroboration_score. This provides reasoning chains with all four scoring dimensions and one composite score in the package without additional retrieval.

ASCII Architecture

EvidenceArtefact
  freshness_score (P147) ─────────────┐
  corroboration_score (P184) ─────────┤
                                       ▼
                        currency_score = sqrt(f × c)
                        currency_band:
                          CURRENT_AND_CORROBORATED (≥ 0.7)
                          CURRENT_UNCORROBORATED   (f≥0.7, c<0.3)
                          STALE_CORROBORATED        (f<0.4, c≥0.7)
                          STALE_UNCORROBORATED      (both<0.4)
                          MODERATE                  (otherwise)
                               │
             ┌─────────────────┼──────────────────────┐
             │                 │                      │
     EvidencePackage     Aggregate Score (P186)   Quality Metrics (P172)
     Item (P174)         currency component       CurrencyDistribution

Operational Detail

[0013] Interaction with Conflict Status: Where an artefact has conflict_status: CONFLICT_PENDING (P161), the corroboration_score component is attenuated by the conflict status (as governed by P184 [0014]). This propagates automatically into the currency_score without requiring the currency score computation to handle conflicts independently.

[0014] Reasoning Chain Guidance: Currency bands provide actionable signals: a reasoning chain receiving CURRENT_AND_CORROBORATED evidence may proceed to first-order reasoning with that evidence directly; STALE_CORROBORATED evidence warrants an explicit “note: evidence is dated” qualifier in the reasoning output; CURRENT_UNCORROBORATED evidence warrants “note: finding is recent but not yet independently confirmed”; STALE_UNCORROBORATED evidence requires the reasoning chain to flag high epistemic uncertainty.

Claims-Exclusion Notice

This specification is published as open-source prior art. No patent claims are asserted by the author in respect of the mechanisms described. Any third party seeking to patent mechanisms substantially equivalent to those described herein is placed on notice of this prior art disclosure.