Purchasing Power Parity (PPP) Comparator 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

t7-097

Effect

Computation or source lookup only

Input and validation requirements

The specification provides no explicit validation behavior for a zero base PPP factor, yet the formula becomes undefined through division by zero. It also leaves amount denomination, sign handling, and country-direction conventions implicit. The formula-branch probe finds no legitimate branch in the stated model; an implementation must not invent one at the factor-ratio parity point.

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": {
    "amount": 100,
    "base_country": "United States",
    "target_country": "India",
    "year": 2021,
    "ppp_series": "GDP PPP",
    "amount_currency": "USD"
  },
  "expected_outputs": {
    "ppp_adjusted_amount": 2256.5,
    "output_currency": "INR",
    "comparison_note": "At 2021 GDP-PPP price levels, USD 100 in the United States corresponds to approximately INR 2,256.50 in India; this is not a market exchange-rate quote."
  },
  "reference_data": {
    "base_country": "United States",
    "base_ppp_conversion_factor_lcu_per_international_dollar": 1,
    "target_country": "India",
    "target_ppp_conversion_factor_lcu_per_international_dollar": 22.565,
    "source_convention": "World Bank ICP 2021 GDP PPP, indicator PA.NUS.PPP; displayed World Bank table values; United States factor 1.000 is the standard international-dollar reference entry."
  },
  "working": "PPP-adjusted amount = amount × (target factor ÷ base factor) = 100 USD × (22.565 INR/international dollar ÷ 1.000 USD/international dollar) = 100 × 22.565 = 2,256.5 INR."
}

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