Salary/Raise Purchasing-Power Check implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t7-027

Effect

Computation or source lookup only

Input and validation requirements

A zero old_salary produces an undefined division, so the instrument requires explicit input validation and rejection. The specification does not state such validation behavior.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "old_salary": 20000,
    "new_salary": 100000,
    "old_period": "CPI-U base period 1982-84",
    "new_period": "2023 annual average"
  },
  "expected_outputs": {
    "real_change": 0.640948,
    "real_percent_change": 64.0948,
    "plain_language_verdict": "The raise exceeded inflation; purchasing power increased."
  },
  "reference_data": {
    "cpi_old": {
      "period": "1982-84",
      "cpi_u_index": 100,
      "source_convention": "widely tabulated standard value; BLS CPI-U index base convention, U.S. city average, all items, not seasonally adjusted"
    },
    "cpi_new": {
      "period": "2023 annual average",
      "cpi_u_index": 304.702,
      "source_convention": "widely tabulated standard value; BLS CPI-U annual average, U.S. city average, all items, not seasonally adjusted, 1982-84=100"
    }
  },
  "working": "Salary ratio = 100000 / 20000 = 5. CPI ratio = 304.702 / 100.000 = 3.04702. Real change = 5 / 3.04702 - 1 = 1.6409475 - 1 = 0.6409475, which rounds to 0.640948. Real percent change = 0.6409475 x 100 = 64.09475%, or 64.0948%. The old CPI is exactly the famous 1982-84 CPI index-base entry of 100."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json