Blood Alcohol Concentration (Widmark estimate)

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Biology, Medicine & Pharmacology (educational estimates only — every panel labeled not-medical-advice)

Tranche

tranche-4

Evidence ID

t4-182

Ledger rows

1

No ledger note is attached.

Review findings

The existing honest-label text is directionally appropriate, but it should explicitly state that 'time to sober' is not a reliable time-to-drive, legal-limit, or fitness-to-operate estimate. Clarify whether BAC is fractional or percent, define β and its units, define standard-drink grams, specify weight units, provide the time-to-sober formula, and enforce positive weight/r and nonnegative reported BAC.

Formula and scope findings

• The formula's first term, Alcohol_g/(Weight_g×r), is a unitless fraction. For an output labeled BAC %, it must be multiplied by 100, assuming BAC is expressed as percent g/dL (for example, 0.08%).
• β is not unit-specified. After converting the Widmark fraction to percent, β must be in BAC percentage points per hour; alternatively, if β is a fraction per hour, the entire formula must remain in fractional units.
• No formula is provided for the claimed time-to-sober output. A conventional estimate would be max(0, current_BAC_percent/β_percent_per_hour), but this definition and the zero/negative handling are absent.
• The fixed r values of 0.68 for males and 0.55 for females are only rough reference values, not universal physiological constants; the sex categories and applicable r range are unspecified.
• The formula does not constrain BAC to be nonnegative, so elapsed time can produce physically nonsensical negative BAC values.
• The meaning of a 'drink' is unspecified; drinks must be converted to grams of pure ethanol before applying the formula.

Unit assumptions

• Weight is converted to grams before calculation; 1 kg = 1000 g and, in the unit-conversion test, 1 lb = 453.59237 g.
• Alcohol_g is grams of pure ethanol, not beverage volume or beverage mass.
• The reported BAC is percent by volume in the usual educational Widmark convention, numerically equivalent to g/dL; therefore the Widmark fraction is multiplied by 100.
• β is assumed to be 0.015 BAC percentage points per hour for the test vectors.
• r is dimensionless, with r=0.68 for the supplied male examples and r=0.55 for the supplied female example.
• Time to sober is interpreted as time for the clamped estimated BAC to reach zero: max(0, estimated_BAC_percent/β).

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The specification does not define beta, does not state whether the formula's BAC is a fraction or percentage, does not define standard-drink gram content, and permits a negative raw BAC at the zero-alcohol boundary. It also has an undefined result at zero body weight.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "alcohol_g": 56,
    "weight_g": 80000,
    "sex": "M",
    "r": 0.68,
    "elapsed_hours": 2,
    "beta_percent_points_per_hour": 0.015
  },
  "expected_outputs": {
    "raw_formula_BAC_percent": 0.07294117647,
    "estimated_BAC_percent": 0.07294117647,
    "time_to_sober_hours": 4.8627451
  },
  "working": "Denominator = 80000 × 0.68 = 54400 g. Widmark fraction = 56 ÷ 54400 = 0.0010294117647. Convert to percent: 0.0010294117647 × 100 = 0.10294117647%. Metabolism = 0.015 × 2 = 0.03 percentage points. Estimated BAC = 0.10294117647 − 0.03 = 0.07294117647%. Time to sober = 0.07294117647 ÷ 0.015 = 4.8627451 hours."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

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

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json