{
  "resourceType": "StructureDefinition",
  "id": "questionnaire-unit",
  "extension": [
    {
      "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
      "valueCode": "fhir"
    },
    {
      "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
      "valueInteger": 1
    }
  ],
  "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-unit",
  "version": "4.0.0",
  "name": "unit",
  "status": "draft",
  "date": "2013-07-04",
  "publisher": "HL7",
  "contact": [
    {
      "telecom": [
        {
          "system": "url",
          "value": "http://www.hl7.org"
        }
      ]
    }
  ],
  "description": "Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and it's purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource.",
  "fhirVersion": "4.0.0",
  "mapping": [
    {
      "identity": "rim",
      "uri": "http://hl7.org/v3",
      "name": "RIM Mapping"
    }
  ],
  "kind": "complex-type",
  "abstract": false,
  "context": [
    {
      "type": "element",
      "expression": "Questionnaire.item"
    },
    {
      "type": "element",
      "expression": "Questionnaire.item.item"
    }
  ],
  "contextInvariant": [
    "type='integer' or type='decimal'"
  ],
  "type": "Extension",
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension",
  "derivation": "constraint",
  "differential": {
    "element": [
      {
        "id": "Extension",
        "path": "Extension",
        "short": "Unit for numeric answer",
        "definition": "Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and it's purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource.",
        "comment": "The human-readable unit is conveyed as a display element.  This element is for computation purposes.",
        "min": 0,
        "max": "1",
        "mapping": [
          {
            "identity": "rim",
            "map": "N/A (MIF-level)"
          }
        ]
      },
      {
        "id": "Extension.extension",
        "path": "Extension.extension",
        "max": "0"
      },
      {
        "id": "Extension.url",
        "path": "Extension.url",
        "type": [
          {
            "code": "uri"
          }
        ],
        "fixedUri": "http://hl7.org/fhir/StructureDefinition/questionnaire-unit"
      },
      {
        "id": "Extension.valueCoding",
        "path": "Extension.valueCoding",
        "type": [
          {
            "code": "Coding"
          }
        ]
      }
    ]
  }
}