Public evidence

engineering.conformity.normalized_error

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

Open calculator API Capability Download JSON MCP Review policy

Verification

9/9 calculation tests · Production surface contract 4/4

Golden tests 0 / 0
Boundary tests 5 / 5
Property tests 4 / 4
Production surface contract 4 / 4
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
Semantic contract PASS
Evidence attested at 2026-09-16T06:44:24.203Z
Last production check 2026-09-16T06:44:24.203Z
Public / cache PASS
Origin PASS
Supplemental domain review Not performed
Named expert review Not performed

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS

Fingerprint sha256:30594010561213e600e36197c86411178a36f5e5912b23d47f98902f0577bd2b

Input schema sha256:6ec0c7626da46df762348ca264b0cee278acb4e5929d857aa046eb758cf3e24c · Output schema sha256:199f4014b5cba69e93ef6b72f724f52eff15c2e5b6b968f8232bad1feb4e0bf4 · 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.

Build & scope

Engine identity and declared limitations.

Tool: normalized-error
Engine: normalized-error
Engine build: 2026-09-15
Evidence core: 2026-09-15T09:13:28.275Z
Rendered: 2026-09-16T22:03:43.736Z
Last reviewed: —

Assumptions

ISO 13528 / ISO/IEC 17043 En with already-expanded Ulab and Uref
|En| ≤ 1 is pass; |En| > 1 is fail
Not zeta (standard u), not TUR, and not an ILAC G8 spec decision

Limitations

Ulab and Uref are already expanded — this page does not compute U = k·u
Not the zeta-score (that uses standard u, not U)
Not TUR and not an ILAC G8 specification decision on y
|En| ≤ 1 is pass; the test does not add a warning zone

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

ISO 13528 — Statistical methods for use in proficiency testing by interlaboratory comparison — Normalized error En using expanded uncertainties
Supports: En = (ylab−xref)/√(Ulab²+Uref²); |En| ≤ 1 is satisfactory
ISO/IEC 17043 — Conformity assessment — General requirements for the competence of proficiency testing providers — Performance evaluation using En
Supports: En is a proficiency-testing performance statistic, not a specification decision rule

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`boundary-en`	boundary	pass	Expected En=0.5 · abs_En=0.5 · decision=pass · Actual En=0.5 · abs_En=0.5 · decision=pass · ylab=2.5 · xref=0 · Ulab=3 · Uref=4
`boundary-en-one`	boundary	pass	Expected En=1 · decision=pass · Actual En=1 · abs_En=1 · decision=pass · ylab=5 · xref=0 · Ulab=3 · Uref=4
`boundary-en-fail`	boundary	pass	Expected En=1.5 · decision=fail · Actual En=1.5 · abs_En=1.5 · decision=fail · ylab=7.5 · xref=0 · Ulab=3 · Uref=4
`boundary-en-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-en-U`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`property-en`	property	pass	0.5
`property-en-one`	property	pass	1
`property-en-fail`	property	pass	fail
`property-en-alias`	property	pass	0.5