Body Surface Area (Du Bois) 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-with-binding-errata

Evidence ID

t2-002

Effect

Computation or source lookup only

Input and validation requirements

The instrument reaches undefined NaN-like results for negative inputs, accepts a mathematically zero but physically invalid weight unless validation is added, and is vulnerable to materially different BSA values when kg/cm versus lb/in conventions are not explicit.

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": {
    "weight_kg": 70,
    "height_cm": 170,
    "formula_select": "Du Bois"
  },
  "expected_outputs": {
    "bsa_m2": 1.81
  },
  "working": "BSA=0.007184·70^0.425·170^0.725. 70^0.425≈6.0837. 170^0.725≈41.4071. 6.0837·41.4071≈251.907. 0.007184·251.907≈1.8097 m², which rounds to 1.810 m²."
}

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-tranche2/tranche2-results.json