Pediatric Engine

When the pediatric engine activates

The engine routes automatically when calculation_model is "AUTO" (the default):

• exact_age ≤ 20 → PEDIATRIC (LMS Box-Cox, CDC/WHO Growth Charts 2000)
• exact_age > 20 → ADULT (Ridge Regression, ANSUR II)

You can also force the engine explicitly: "calculation_model": "PEDIATRIC".

Age categories

Set age_category explicitly, or let calculation_model: "AUTO" derive it from exact_age.

Zero measurements required

The pediatric engine does not need any anchor measurements. Age and gender alone produce a complete profile:

{
  "input_data": {
    "input_unit_system": "metric",
    "subject": {
      "gender": "female",
      "exact_age": 7.0,
      "age_category": "CHILD"
    },
    "anchors": {}
  },
  "output_settings": {
    "calculation": {
      "calculation_model": "AUTO",
      "target_region": "EUROPE",
      "body_build_type": "CIVILIAN"
    },
    "requested_dimensions": { "bundle": "FULL_BODY" }
  }
}

Supplying a measured body_height or body_mass overrides the LMS prediction and improves downstream accuracy.

How it works

Step 1: LMS Box-Cox method (CDC Growth Charts 2000) produces age-and-gender-specific body_height and body_mass at the 50th percentile.

Step 2: These values are passed as anchors into a scaled adult Ridge Regression pass to generate the full 130-dimension profile.

Confidence scores:

• LMS-derived dimensions (body_height, body_mass, head_circumference ≤ 36 months): confidence_score: 99
• All Ridge hybrid predictions: capped at 80

Known limitations

Biological limits gate

Pediatric outputs are validated against CDC P1–P99 age-banded limits. Values outside this range are flagged with biological_limit_status: "OUT_OF_BOUNDS". The limit bands are interpolated between CDC LMS table entries.