Public evidence

engineering.process.cpm_performance

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 6 / 6
Property tests 3 / 3
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:f741626ec143278c83a75491a303ce551e8117550b0dca6b8d91ca9648b12dad

Input schema sha256:9aa6499ae117f60740e75e99e6f8a1d2ababff4c4100ee4a26c8cd07aecc4b5b · Output schema sha256:d2ef602dda6a16afc3253fb9fb3156e5534bf34b819f93a75f05f7eb8ccb5309 · 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: cpm-performance
Engine: cpm-performance
Engine build: 2026-09-16
Evidence core: 2026-09-16T21:07:40.795Z
Rendered: 2026-09-16T22:38:08.850Z
Last reviewed: —

Assumptions

Overall Taguchi Ppm = (USL−LSL)/(6√(s²+(x̄−target)²)) from a sample. s is summarizeSample.
Not design-stage Cpm, not Pp/Ppk (no target), and not a 1.33 verdict.

Limitations

Overall sample s — not design-stage Cpm from a stated σ
Not Pp/Ppk (those have no target in the denominator)
This page does not issue a Ppm≥1.33 verdict

Sources

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

Chan, Cheng, and Spiring — A new measure of process capability: Cpm — Cpm = (USL−LSL)/(6√(σ²+(μ−T)²)); overall analog uses sample s
Supports: Ppm is the overall-sample counterpart of Cpm
ISO 22514-2 — Statistical methods in process management — Capability and performance — Capability vs performance; target-based indices
Supports: This page is overall performance, not design-stage Cpm

Published checks

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

ID	Kind	Status	Detail
`boundary-ppm`	boundary	pass	Expected Ppm=1 · xbar=6 · s=2 · offset=0 · Actual n=3 · Ppm=1 · xbar=6 · s=2 · target=6 · offset=0 · ddof=1 · lsl=0
`boundary-ppm-shift`	boundary	pass	Expected Ppm=0.8944271909999159 · Actual n=3 · Ppm=0.8944271909999159 · xbar=8 · s=1 · target=6 · offset=2 · ddof=1 · lsl=0
`boundary-ppm-flat-off`	boundary	pass	Expected Ppm=1 · s=0 · Actual n=3 · Ppm=1 · xbar=8 · s=0 · target=6 · offset=2 · ddof=1 · lsl=0
`boundary-ppm-n1`	boundary	pass	Expected VALUE_OUT_OF_RANGE · Actual VALUE_OUT_OF_RANGE
`boundary-ppm-flat-on`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`boundary-ppm-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`property-ppm`	property	pass	1
`property-ppm-shift`	property	pass	2/√5
`property-ppm-flat-off`	property	pass	1