engineering.measurement.error

Three distinct suites: educational examples on the calculator page, this legacy regression count (6/6 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.0.1 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-25.o2-o3. Calculation version 1.0.1. CVP 1.0.0-proposed. 4/4 golden · 2/2 CVP boundary · 3/3 invalid · 1/1 property · 1/1 metamorphic · 8/8 O3 · 2/2 cross-interface · 6/6 CVP contract. digest 34ab16e68069. O2: signed measurement error vs a separate-module subtraction (≤2 ULP). Not percent error, not En, and not a z-score. ≤2 ULP vs O3 applies only to the published tabulated measurement-error vectors. Not percent error.

• Golden (oracle-backed) 4 / 4
• CVP boundary 2 / 2
• Invalid input 3 / 3
• Property 1 / 1
• Metamorphic 1 / 1
• O3 high-precision 8 / 8
• Cross-interface 2 / 2
• CVP contract 6 / 6
• Interfaces PASS · UI (SSR) / REST / MCP
• Interface claim ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
• Verified scope Signed measurement error ε = ylab − xref, plus the relative error when the reference is not zero, + O3 mpmath tabulated measurement error.
• Assurance Engineering
• Deferred Not percent error, not En, and not a z-score.

• release artifacts aligned PASS
• schema output required declared PASS
• schema valid input executes PASS
• engine success output validates schema PASS
• schema rejects incomplete input PASS
• rest success payload validates schema PASS

Fingerprint sha256:3cd6220e88e5f57f47a39b7a87cf76778af8fbd920ed3ee4fda53af4a8f5fd3b

Input schema sha256:b18c8d2bcfc95a619bed620ec0ecd564ad9b1ee49f4572657e38eda2033f8f07 · Output schema sha256:fc710d774412f0e9f9fa075970c94eea14bf873bad7ef68aeb95ed8ad04da7d6 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Tool

measurement-error

Engine

measurement-error

Engine build

2026-09-24

Evidence core

2026-09-24T21:56:52.174Z

Rendered

2026-10-23T01:27:11.176Z

Last reviewed

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Assumptions

• VIM measurement error ε = ylab − xref (signed). Relative error is ε/xref when xref ≠ 0.
• Not percent error (×100), not En, not zeta, not z-score, and not an ILAC G8 spec decision.

Limitations

• Signed error — this page does not multiply by 100 (that is percent error)
• Not En, zeta, or z-score (those divide by U, u, or σ_pt)
• Not an ILAC G8 specification decision
• Relative error is undefined when xref = 0