Rule of 70 GDP Doubling Time 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

t5-196

Effect

Computation or source lookup only

Input and validation requirements

A zero growth rate causes division by zero and must be rejected or returned as undefined. Negative growth produces a raw negative quotient that is not a meaningful doubling time and therefore requires an implicit validity branch. The percent-versus-decimal convention can also produce a materially different result if the input unit is misunderstood.

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": {
    "annual_gdp_growth_rate_percent": 2.5
  },
  "expected_outputs": {
    "years_to_double": 28
  },
  "working": "Apply Rule of 70: years ≈ 70 / growth rate %. Substitute 2.5: 70 / 2.5 = 28. Expected result: 28 years."
}

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-tranche5/tranche5-results.json