{
"description": "The population basis specifies the type of elements in the population. For a subject-based measure, this is boolean (because the subject and the population basis are the same, and the population criteria define yes/no values for each individual in the population). For measures that have a population basis that is different than the subject, this element specifies the type of the population basis. For example, an encounter-based measure has a subject of Patient and a population basis of Encounter, and the population criteria all return lists of Encounters. Note that the subject of a measure can be found in the element [subject[x].](https://hl7.org/fhir/uv/cqm/StructureDefinition-cqm-computablemeasure-definitions.html#Measure.subject[x])",
"_filename": "StructureDefinition-cqm-populationBasis.json",
"package_name": "hl7.fhir.uv.cqm",
"date": "2025-09-11T18:58:45+00:00",
"derivation": "constraint",
"publisher": "HL7 International / Clinical Quality Information",
"fhirVersion": "4.0.1",
"jurisdiction": [ {
"coding": [ {
"code": "001",
"system": "http://unstats.un.org/unsd/methods/m49/m49.htm"
} ]
} ],
"purpose": "A measure specification needs to be able to specify the expected result type of each population criteria. This value SHALL be consistent with the result type of all population-level criteria in the measure.",
"name": "CQMPopulationBasis",
"mapping": [ {
"uri": "http://hl7.org/v3",
"name": "RIM Mapping",
"identity": "rim"
} ],
"abstract": false,
"type": "Extension",
"experimental": "false",
"resourceType": "StructureDefinition",
"title": "CQM Population Basis",
"package_version": "1.0.0",
"extension": [ {
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
"valueCode": "cqi"
}, {
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
"valueInteger": 4,
"_valueInteger": {
"extension": [ {
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
"valueCanonical": "http://hl7.org/fhir/uv/cqm/ImplementationGuide/hl7.fhir.uv.cqm"
} ]
}
}, {
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
"valueCode": "trial-use",
"_valueCode": {
"extension": [ {
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
"valueCanonical": "http://hl7.org/fhir/uv/cqm/ImplementationGuide/hl7.fhir.uv.cqm"
} ]
}
} ],
"snapshot": {
"element": [ {
"constraint": [ {
"key": "ele-1",
"human": "All FHIR elements must have a @value or children",
"xpath": "@value|f:*|h:div",
"source": "http://hl7.org/fhir/StructureDefinition/Element",
"severity": "error",
"expression": "hasValue() or (children().count() > id.count())"
}, {
"key": "ext-1",
"human": "Must have either extensions or value[x], not both",
"xpath": "exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')])",
"source": "http://hl7.org/fhir/StructureDefinition/Extension",
"severity": "error",
"expression": "extension.exists() != value.exists()"
}, {
"key": "popBasis-1",
"human": "If DataRequirement.type is present, it may only contain the elements 'profile' and 'codeFilter'.",
"severity": "error",
"expression": "value.exists() and value.is(DataRequirement) implies ( value.as(DataRequirement).type.exists() and value.as(DataRequirement).limit.empty() and value.as(DataRequirement).sort.empty() and value.as(DataRequirement).dateFilter.empty() and value.as(DataRequirement).subject.empty() and value.as(DataRequirement).mustSupport.empty())"
} ],
"path": "Extension",
"min": 0,
"definition": "The population basis specifies the type of elements in the population. For a subject-based measure, this is boolean (because the subject and the population basis are the same, and the population criteria define yes/no values for each individual in the population). For measures that have a population basis that is different than the subject, this element specifies the type of the population basis. For example, an encounter-based measure has a subject of Patient and a population basis of Encounter, and the population criteria all return lists of Encounters.",
"isModifier": false,
"short": "What type of population",
"max": "*",
"id": "Extension",
"condition": [ "ele-1" ],
"comment": "In Health Quality Measure Format, this was referred to as the Item Count metadata attribute. If the populationBasis is specified as a data requirement, the type SHALL be present, profile and codeFilter MAY be present, and no other elements are allowed. This usage allows population basis to be stated with more specificity, e.g. CT Scans, rather than just DiagnosticReport.",
"base": {
"max": "*",
"min": 0,
"path": "Extension"
}
}, {
"path": "Extension.id",
"min": 0,
"definition": "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.",
"isModifier": false,
"short": "Unique id for inter-element referencing",
"mapping": [ {
"map": "n/a",
"identity": "rim"
} ],
"type": [ {
"code": "http://hl7.org/fhirpath/System.String",
"extension": [ {
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
"valueUrl": "string"
} ]
} ],
"representation": [ "xmlAttr" ],
"max": "1",
"id": "Extension.id",
"base": {
"max": "1",
"min": 0,
"path": "Element.id"
},
"isSummary": false
}, {
"constraint": [ {
"key": "ele-1",
"human": "All FHIR elements must have a @value or children",
"xpath": "@value|f:*|h:div",
"source": "http://hl7.org/fhir/StructureDefinition/Element",
"severity": "error",
"expression": "hasValue() or (children().count() > id.count())"
}, {
"key": "ext-1",
"human": "Must have either extensions or value[x], not both",
"xpath": "exists(f:extension)!=exists(f:*[starts-with(local-name(.), \"value\")])",
"source": "http://hl7.org/fhir/StructureDefinition/Extension",
"severity": "error",
"expression": "extension.exists() != value.exists()"
} ],
"path": "Extension.extension",
"min": 0,
"definition": "May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.",
"isModifier": false,
"short": "Additional content defined by implementations",
"mapping": [ {
"map": "n/a",
"identity": "rim"
} ],
"slicing": {
"rules": "open",
"description": "Extensions are always sliced by (at least) url",
"discriminator": [ {
"path": "url",
"type": "value"
} ]
},
"type": [ {
"code": "Extension"
} ],
"alias": [ "extensions", "user content" ],
"max": "*",
"id": "Extension.extension",
"comment": "There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.",
"base": {
"max": "*",
"min": 0,
"path": "Element.extension"
},
"isSummary": false
}, {
"path": "Extension.url",
"min": 1,
"definition": "Source of the definition for the extension code - a logical name or a URL.",
"isModifier": false,
"short": "identifies the meaning of the extension",
"fixedUri": "http://hl7.org/fhir/uv/cqm/StructureDefinition/cqm-populationBasis",
"mapping": [ {
"map": "N/A",
"identity": "rim"
} ],
"type": [ {
"code": "uri"
} ],
"representation": [ "xmlAttr" ],
"max": "1",
"id": "Extension.url",
"comment": "The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.",
"base": {
"max": "1",
"min": 1,
"path": "Extension.url"
},
"isSummary": false
}, {
"constraint": [ {
"key": "ele-1",
"human": "All FHIR elements must have a @value or children",
"xpath": "@value|f:*|h:div",
"source": "http://hl7.org/fhir/StructureDefinition/Element",
"severity": "error",
"expression": "hasValue() or (children().count() > id.count())"
} ],
"path": "Extension.value[x]",
"min": 0,
"definition": "Value of extension - must be one of a constrained set of the data types (see [Extensibility](http://hl7.org/fhir/R4/extensibility.html) for a list).",
"isModifier": false,
"short": "Value of extension",
"mapping": [ {
"map": "N/A",
"identity": "rim"
} ],
"type": [ {
"code": "code"
}, {
"code": "DataRequirement"
} ],
"binding": {
"strength": "required",
"valueSet": "http://hl7.org/fhir/ValueSet/all-types",
"description": "The type of elements in the population"
},
"max": "1",
"id": "Extension.value[x]",
"base": {
"max": "1",
"min": 0,
"path": "Extension.value[x]"
},
"isSummary": false
} ],
"extension": [ {
"url": "http://hl7.org/fhir/tools/StructureDefinition/snapshot-base-version",
"valueString": "4.0.1"
} ]
},
"status": "active",
"id": "dfb1f9e3-107b-4f6d-9b99-1b811c2264fb",
"kind": "complex-type",
"url": "http://hl7.org/fhir/uv/cqm/StructureDefinition/cqm-populationBasis",
"identifier": [ {
"value": "urn:oid:2.16.840.1.113883.4.642.40.61.42.21",
"system": "urn:ietf:rfc:3986"
} ],
"context": [ {
"type": "element",
"expression": "Measure"
}, {
"type": "element",
"expression": "Measure.group"
}, {
"type": "element",
"expression": "Measure.group.population"
} ],
"version": "1.0.0",
"differential": {
"element": [ {
"id": "Extension",
"max": "*",
"min": 0,
"path": "Extension",
"short": "What type of population",
"comment": "In Health Quality Measure Format, this was referred to as the Item Count metadata attribute. If the populationBasis is specified as a data requirement, the type SHALL be present, profile and codeFilter MAY be present, and no other elements are allowed. This usage allows population basis to be stated with more specificity, e.g. CT Scans, rather than just DiagnosticReport.",
"constraint": [ {
"key": "popBasis-1",
"human": "If DataRequirement.type is present, it may only contain the elements 'profile' and 'codeFilter'.",
"severity": "error",
"expression": "value.exists() and value.is(DataRequirement) implies ( value.as(DataRequirement).type.exists() and value.as(DataRequirement).limit.empty() and value.as(DataRequirement).sort.empty() and value.as(DataRequirement).dateFilter.empty() and value.as(DataRequirement).subject.empty() and value.as(DataRequirement).mustSupport.empty())"
} ],
"definition": "The population basis specifies the type of elements in the population. For a subject-based measure, this is boolean (because the subject and the population basis are the same, and the population criteria define yes/no values for each individual in the population). For measures that have a population basis that is different than the subject, this element specifies the type of the population basis. For example, an encounter-based measure has a subject of Patient and a population basis of Encounter, and the population criteria all return lists of Encounters."
}, {
"id": "Extension.url",
"path": "Extension.url",
"type": [ {
"code": "uri"
} ],
"fixedUri": "http://hl7.org/fhir/uv/cqm/StructureDefinition/cqm-populationBasis"
}, {
"id": "Extension.value[x]",
"path": "Extension.value[x]",
"type": [ {
"code": "code"
}, {
"code": "DataRequirement"
} ],
"binding": {
"strength": "required",
"valueSet": "http://hl7.org/fhir/ValueSet/all-types",
"description": "The type of elements in the population"
}
} ]
},
"contact": [ {
"telecom": [ {
"value": "http://www.hl7.org/Special/committees/cqi",
"system": "url"
} ]
} ],
"baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension"
}