description: The primary measure of variance/uncertainty of the value (the square root of the sum of the squares of the differences between all data points and the mean). package_name: hl7.fhir.uv.extensions.r4 derivation: constraint name: Uncertainty type: Extension elements: extension: {index: 0} url: pattern: {type: uri, value: 'http://hl7.org/fhir/StructureDefinition/iso21090-uncertainty'} type: uri index: 1 value: choices: [valueDecimal] index: 3 valueDecimal: {type: decimal, choiceOf: value, index: 4} package_version: 5.3.0-ballot-tc1 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/iso21090-uncertainty base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.3.0-ballot-tc1 required: [value, valueDecimal]