---
title: "Should the vault's single source_tier field split into two axes — source reliability separate from claim credibility — the way intelligence doctrine and RAG both do?"
type: "question"
status: "open"
date_raised: "2026-07-11T00:00:00.000Z"
tags: ["vault-design","source-tiers","provenance","epistemics","meta"]
---


The Admiralty-Code hop ([[observation-intelligence-doctrine-and-rag-independently-derived-a-two-axis-source-model]]) surfaces a direct challenge to the vault's own design. Both Cold-War intelligence doctrine ([[claim-admiralty-code-grades-sources-on-two-independent-axes]]) and 2025 retrieval research ([[claim-reliability-aware-rag-estimates-source-reliability-separately-from-relevance]]) grade a report on **two** axes — how reliable the *source* is, separately from how credible the *specific claim* is. The vault's `source_tier` fuses these into one number.

**The question.** Should a claim-note carry two fields — e.g. a source-reliability tier and a per-claim credibility/corroboration grade — instead of one `source_tier`?

**The case for.** The vault already half-does this: `audit_status`, `[unverified-quant]` flags, and the "one confirmed source vs uncorroborated" distinction are credibility-of-the-claim signals living *outside* `source_tier`. Making the second axis explicit could sharpen retrieval gating.

**The case against.** [[claim-source-reliability-and-credibility-are-not-judged-independently|Trained analysts empirically cannot keep the two axes independent]] — they over-weight source track record and avoid inconsistent pairings. If humans (and, per [[claim-document-text-degrades-llm-source-authority-judgment|AuthorityBench]], models) can't hold the axes apart, a second field may add false precision rather than honesty. The single tier may be an *admission* that the split doesn't survive contact with a real evaluator.

**What I'd need to answer it.** A pass over how `source_tier` + `audit_status` + flags actually interact in ~20 notes; whether the fusion has ever caused a mis-grade; and whether the retrieval layer (spec §7's gating rule) would benefit from a separate credibility axis. This is a design decision for Cali, not a unilateral schema change.

**Candidate next move.** Draft a one-page design memo weighing the two-axis option against the current fused tier, citing the three underlying claim-notes; leave the schema untouched until Cali rules.

## Progress

**2026-07-21 (partial — stays open).** A batch capture
(`10-inbox/raw/2026-07-20-should-the-vaults-single-source-tier-field-split.md`)
added a third and fourth independently-converging domain and a check on what
the existing "axes leak" finding actually recommends: evidence-based
medicine's GRADE framework
([[claim-grade-splits-quality-of-evidence-from-strength-of-recommendation]])
and the CRAAP library-science test
([[claim-craap-test-splits-authority-from-accuracy]]) both draw the same
source-vs-content line independently; and Kelly et al.'s own response to
"raters can't keep the axes apart" turns out to be a richer nine-cell matrix,
not a call to collapse
([[claim-kelly-et-al-propose-richer-joint-matrix-not-axis-collapse]]). A
search for practitioner opinion on the merge-vs-split question found writers
arguing only to keep the axes separate
([[claim-no-practitioner-source-found-advocating-merging-reliability-credibility-axes]]),
though that search was not exhaustive.

This strengthens the case-for column but does **not** close the question: no
inter-rater-reliability, cognitive-load, or rater-burden data on two-axis
systems turned up in this pass either (checked specifically in Kelly et al.
and came up empty), so the cost side of the tradeoff — whether a second field
would sharpen retrieval gating or just add a number nobody keeps honestly
independent — remains as unaddressed as it was on 2026-07-11. Still a design
decision for Cali, not something four converging citations settle by
themselves. Left open.