{
  "capability_id": "math.percent_change",
  "tool_id": "percent-change",
  "engine": "percent-change",
  "calculation_version": "1.1.0",
  "generated_at": "2026-10-21T10:45:15.715Z",
  "engine_build": "2026-10-14",
  "test_count": 8,
  "passed": 8,
  "failed": 0,
  "tests_summary": {
    "golden": {
      "passed": 6,
      "total": 6
    },
    "boundary": {
      "passed": 2,
      "total": 2
    },
    "property": {
      "passed": 0,
      "total": 0
    }
  },
  "engine_tested": true,
  "expert_reviewed": false,
  "internally_reviewed": false,
  "review_kind": null,
  "source_checked": true,
  "reviewed_by": null,
  "reviewer_role": null,
  "last_reviewed": null,
  "expert_review": {
    "status": "optional_not_performed",
    "reviewer": null,
    "scope": [
      "formula",
      "input semantics",
      "assumptions",
      "limitations",
      "sources",
      "tests"
    ],
    "note": "Domain expert review is optional under CVP (CVP-EXP-01). Absence does not block CVP Verified. See Review policy for supplemental domain assurance."
  },
  "internal_review": {
    "status": "not_applicable",
    "reviewer": null
  },
  "page": "https://www.calculatorx.com/calc/math/percentage-change",
  "api": "https://www.calculatorx.com/api/v1/calc/percent-change",
  "schema_input": "https://www.calculatorx.com/schemas/math.percent_change.input.json",
  "schema_output": "https://www.calculatorx.com/schemas/math.percent_change.output.json",
  "assumptions": [
    "Interactive evaluation runs locally in the browser. Shared URLs and REST evaluate the same versioned engine (query SSR).",
    "CVP interface evidence is UI (SSR) query-result HTML, REST, and MCP (MCP reuses the calc API handler). That is interface-result consistency, not a live browser session, cache switching, or end-to-end UI test.",
    "Signed-change convention: denominator is |V₁|, so a move from −100 to −50 is a +50% increase. Some definitions use V₁ without absolute value or restrict to positive baselines.",
    "Exactly two fields are inputs. Explicit solve_for selects the output. If all three are supplied without solve_for, they are checked for consistency rather than overwritten.",
    "Solving for V₁ is not always unique. The engine returns both valid initials when they exist."
  ],
  "limitations": [
    "V₁ = 0 → INITIAL_VALUE_ZERO",
    "Invalid reverse solve → NO_REAL_SOLUTION; some cases INFINITELY_MANY"
  ],
  "boundary_conditions": [
    "V₁ = 0 → INITIAL_VALUE_ZERO (percent change undefined)",
    "Fewer than two inputs → MISSING_REQUIRED_INPUT",
    "Invalid solve_for → INVALID_SOLVE_FOR",
    "Positive-initial reverse branch: 1 + P/100 = 0 (P = −100%) is omitted",
    "Negative-initial reverse branch: 1 − P/100 = 0 (P = +100%) is omitted",
    "Solve V₁ may have 0, 1, or 2 solutions",
    "V₂ = 0, P = −100%, solve V₁ → INFINITELY_MANY (any V₁ > 0)",
    "V₂ = 0, P = +100%, solve V₁ → INFINITELY_MANY (any V₁ < 0)",
    "V₂ = 0 and P ≠ ±100%, solve V₁ → NO_REAL_SOLUTION",
    "All three values filled without solve_for and not matching the formula → INCONSISTENT_INPUTS"
  ],
  "sources": [
    {
      "title": "Curran-Everett — Explorations in statistics: the analysis of change",
      "section": "Relative change as (final − initial) / initial",
      "url": "https://journals.physiology.org/doi/full/10.1152/advan.00018.2015",
      "supports": "Documents a relative-change definition that divides directly by the initial value rather than |initial|. Negative-baseline percentage change is therefore not a single universal convention.",
      "kind": "reference",
      "accessed": "2026-08-28"
    },
    {
      "title": "CalculatorX signed-change convention",
      "section": "|V₁| denominator, piecewise inverse, and multiple V₁ solutions",
      "supports": "% change = (V₂−V₁)/|V₁|×100% (undefined at V₁ = 0). Inverse: V₂ = V₁(1+P/100) if V₁>0 and V₁(1−P/100) if V₁<0. Solving V₁ publishes both signed branches, INFINITELY_MANY at V₂=0 with P=±100%, and NO_REAL_SOLUTION when no branch is valid.",
      "kind": "definition"
    },
    {
      "title": "NIST — SI Unit Rules and Style Conventions",
      "section": "Percent and fractions",
      "url": "https://physics.nist.gov/cuu/Units/checklist.html",
      "supports": "The symbol % represents the number 0.01. Thus p% = p/100 and a part of p% of base b equals b×p/100; inverse percentage equations are algebraic rearrangements. CalculatorX’s negative-baseline signed-change convention is separately specified, not attributed to NIST. Mathematical reference only; not implementation validation or an endorsement of CalculatorX.",
      "kind": "reference",
      "publisher": "National Institute of Standards and Technology"
    }
  ],
  "methods": [],
  "fingerprint": "sha256:fcc1ae93840bcc952ec705764db517dec8db909e0f8a2fdfa5b4cad6d54f0572",
  "tier": "engine_tested",
  "verification": {
    "tests": {
      "passed": 8,
      "total": 8,
      "golden": 6,
      "boundary": 2,
      "property": 0
    },
    "contract_checks": {
      "passed": 5,
      "total": 5
    }
  },
  "evidence_core_generated_at": "2026-10-14T05:05:51.930Z",
  "rendered_at": "2026-10-21T10:45:15.715Z",
  "release_integrity": {
    "status": "verified",
    "scope": "workspace",
    "production_attestation_required": true,
    "calculation_version": "1.1.0",
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    "contract_checks": {
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      "passed": 5,
      "failed": 0,
      "items": [
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          "id": "release-artifacts-aligned",
          "status": "pass",
          "detail": "1.1.0"
        },
        {
          "id": "schema-output-required-declared",
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        },
        {
          "id": "schema-valid-input-executes",
          "status": "pass"
        },
        {
          "id": "engine-success-output-validates-schema",
          "status": "pass"
        },
        {
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    "report": "https://www.calculatorx.com/.well-known/calculatorx-release-integrity.json"
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    "policy": "calculatorx-public-evidence-v1",
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