Mid-Parental Height Predictor

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

t4-230

Ledger rows

1

No ledger note is attached.

Review findings

No division-by-zero hazard exists. The arithmetic formulas pass under the stated centimeter assumptions, but the specification needs explicit unit handling, accepted sex-input semantics, validation constraints, rounding rules, and provenance/interpretation for the ±8.5 cm range.

Formula and scope findings

• The mid-parental formulas are standard when parental heights and constants use the same units: boys = (father + mother + 13 cm) / 2 and girls = (father + mother - 13 cm) / 2.
• The ±8.5 cm spread is a commonly used population estimate, but it is not universal; the source, population, and whether it represents a prediction interval or a clinical target range are unspecified.

Unit assumptions

• The parental heights must be supplied in centimeters for the stated +13, −13, and ±8.5 values to be dimensionally correct.
• If heights are supplied in inches, they must be converted first: inches × 2.54 = centimeters; alternatively, the sex adjustment must be converted to 5.118 inches and the spread to approximately 3.346 inches.
• The output range is assumed to be [predicted height − 8.5 cm, predicted height + 8.5 cm].

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The plain arithmetic formulas produce a numeric result for the exactly-zero parental-height boundary instead of inherently rejecting a physically invalid input, and extreme finite JavaScript inputs overflow to Infinity. Unspecified height units also permit materially divergent interpretations.

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": {
    "father_height_cm": 180,
    "mother_height_cm": 165,
    "child_sex": "boy"
  },
  "expected_outputs": {
    "predicted_height_cm": 179,
    "range_cm": {
      "lower": 170.5,
      "upper": 187.5
    }
  },
  "working": "Sum parental heights: 180 + 165 = 345 cm. Add the boy adjustment: 345 + 13 = 358 cm. Divide by 2: 358 / 2 = 179 cm. Range: 179 − 8.5 = 170.5 cm; 179 + 8.5 = 187.5 cm."
}

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