See Understanding the Group Resource for additional information. The ExposureGroup Profile is named ‘ExposureGroup’ rather than ‘InterventionGroup’ because it may be used in observational research as well as interventional research. When describing interventional research, such as a clinical trial, the exposures are often called interventions.

An example from the QUARTET USA trial will be described here and can be viewed at QUARTET USA Trial Quadpill group.

The concepts needed to describe the intervention group for the QUARTET USA trial include:

1. The group is an ‘actual’ group of people.
2. The group has 32 members.
3. The group membership criteria is defined as meeting both of 2 characteristics: a. Being a member of the Enrolled Group for QUARTET USA Trial b. Assigned to Quadpill Intervention

We start by creating a FHIR Group Resource with an ExposureGroup Profile. This instance of Group Resource is being used to define the actual group, either with a quantity or a list of members, therefore the Group.membership element has a value of “enumerated”. For an enumerated Group, a Group.type element is required, and the Group.type element has a value of “person”.

The Group.quantity element has an unsignedInt datatype (allowing integer values without a negative sign) because it is for a simple count of group members. The Group.quantity element has a value of 32 in this example.

The definition of group membership is described with two characteristics, so a Group.combinationMethod element is needed to define how these characteristics are combined. In this case, because both characteristics are required to be met, the Group.combinationMethod element has a value of “all-of”.

The characteristic of being a member of the Enrolled Group for QUARTET USA Trial can be described with a .code element representing “member of” and a .value[x] element representing “ the Enrolled Group for QUARTET USA Trial”.

The corresponding JSON for this characteristic is:

{
  "code" : {
    "text" : "Member of"
  },
  "valueReference" : {
    "reference" : "Group/372797",
    "type" : "Group",
    "display" : "Enrolled Group for QUARTET USA Trial"
  },
  "exclude" : false,
  "description" : "Enrolled in QUARTET USA Trial"
}

The characteristic of being assigned to Quadpill intervention can be described with a .code element representing “assigned to” and a .value[x] element representing “Quadpill intervention”. Because the Quadpill intervention is represented with a Dosage datatype, an ActivityDefinition Resource was selected for its expression.

The corresponding JSON for this characteristic is:

{
  "code" : {
    "text" : "Assigned to"
  },
  "valueReference" : {
    "reference" : "ActivityDefinition/375159",
    "type" : "ActivityDefinition",
    "display" : "Quadpill once daily"
  },
  "exclude" : false,
  "description" : "Assigned to Quadpill Intervention"
}

• Key Elements Table
• Differential Table
• Snapshot Table
• Statistics/References
• All

Name	Flags	Card.	Type	Description & Constraints    Filter: Bindings Constraints Obligations
Group	C	0..*	GroupR6	Group of multiple entities Interfaces Implemented: CanonicalResource Constraints: cnl-2
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
contained		0..*	Resource	Contained, inline Resources
Slices for extension				Content/Rules for all slices
extension:author		0..*	ContactDetail	Who authored the artifact URL: http://hl7.org/fhir/StructureDefinition/artifact-author
extension:citeAs		0..1	markdown	Citation for this Resource URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/cite-as
extension:relatesTo		0..*	(Complex)	Related artifact URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to
extension:RelatesToWithQuotation		0..*	(Complex)	Related artifact with quoted portion URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to-with-quotation
extension:characteristicExpression		0..1	Expression	Criteria for group membership URL: http://hl7.org/fhir/StructureDefinition/characteristicExpression
extension:publicationStatus		0..1	CodeableConcept	Publication status URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/artifact-publication-status Binding: Cited Artifact Status Type (preferred)
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored
status	?!Σ	0..1	code	draft | active | retired | unknown Binding: PublicationStatus (required): The lifecycle status of an artifact.
membership	Σ	1..1	code	definitional | conceptual | enumerated Binding: GroupMembershipBasis (required): The basis for membership in a group Required Pattern: enumerated
combinationMethod	?!Σ	0..1	code	all-of | any-of | at-least | at-most | except-subset Binding: GroupCharacteristicCombination (required)
Documentation for this format

Terminology Bindings

Path	Status	Usage	ValueSet	Version	Source
Group.status	Base	required	PublicationStatus	📍6.0.0-ballot3	FHIR Std.
Group.membership	Base	required	Group Membership Basis	📍6.0.0-ballot3	FHIR Std.
Group.combinationMethod	Base	required	Group Characteristic Combination	📍6.0.0-ballot3	FHIR Std.

Constraints

Id	Grade	Path(s)	Description	Expression
cnl-2	error	Group	Group.type SHALL be defined if Group.membership is either 'definitional' or 'enumerated'	Group.type.exists() or (Group.membership = 'conceptual')
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children	hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both	extension.exists() != value.exists()

This structure is derived from GroupR6

Name	Flags	Card.	Type	Description & Constraints    Filter: Bindings Constraints Obligations
Group		0..*	GroupR6	Group of multiple entities Interfaces Implemented: CanonicalResource
membership		1..1	code	definitional | conceptual | enumerated Required Pattern: enumerated
Documentation for this format

Name	Flags	Card.	Type	Description & Constraints    Filter: Bindings Constraints Obligations
Group	C	0..*	GroupR6	Group of multiple entities Interfaces Implemented: CanonicalResource Constraints: cnl-2
id	Σ	0..1	id	Logical id of this artifact
meta	Σ	0..1	Meta	Metadata about the resource
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
language		0..1	code	Language of the resource content Binding: AllLanguages (required): IETF language tag for a human language Additional Bindings Purpose CommonLanguages Starter
text		0..1	Narrative	Text summary of the resource, for human interpretation This profile does not constrain the narrative in regard to content, language, or traceability to data elements
contained		0..*	Resource	Contained, inline Resources
Slices for extension		0..*	Extension	Extension Slice: Unordered, Open by value:url
extension:author		0..*	ContactDetail	Who authored the artifact URL: http://hl7.org/fhir/StructureDefinition/artifact-author
extension:citeAs		0..1	markdown	Citation for this Resource URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/cite-as
extension:relatesTo		0..*	(Complex)	Related artifact URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to
extension:RelatesToWithQuotation		0..*	(Complex)	Related artifact with quoted portion URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to-with-quotation
extension:characteristicExpression		0..1	Expression	Criteria for group membership URL: http://hl7.org/fhir/StructureDefinition/characteristicExpression
extension:publicationStatus		0..1	CodeableConcept	Publication status URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/artifact-publication-status Binding: Cited Artifact Status Type (preferred)
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored
url	ΣC	0..1	uri	Canonical identifier for this Group, represented as an absolute URI (globally unique) Constraints: cnl-1
identifier	Σ	0..*	Identifier	Business Identifier for this Group
version	Σ	0..1	string	Business version of the Group
versionAlgorithm[x]	Σ	0..1		How to compare versions Binding: VersionAlgorithm (extensible)
versionAlgorithmString			string
versionAlgorithmCoding			Coding
name	Σ	0..1	string	Label for Group
title	Σ	0..1	string	Name for this Group (human friendly)
status	?!Σ	0..1	code	draft | active | retired | unknown Binding: PublicationStatus (required): The lifecycle status of an artifact.
experimental	Σ	0..1	boolean	For testing only - never for real usage
date	Σ	0..1	dateTime	Date last changed
publisher	Σ	0..1	string	Name of the publisher/steward (organization or individual)
contact	Σ	0..*	ContactDetail	Contact details for the publisher
description		0..1	markdown	Natural language description of the group
useContext	Σ	0..*	UsageContext	The context that the content is intended to support
purpose		0..1	markdown	Why this Group is defined
copyright		0..1	markdown	Use and/or publishing restrictions
copyrightLabel		0..1	string	Copyright holder and year(s)
type	Σ	0..1	code	person | animal | practitioner | device | careteam | healthcareservice | location | organization | relatedperson | specimen | medication | substance | biologicallyDerivedProduct | nutritionProduct Binding: GroupType (required): Types of resources that are part of group.
membership	Σ	1..1	code	definitional | conceptual | enumerated Binding: GroupMembershipBasis (required): The basis for membership in a group Required Pattern: enumerated
code	Σ	0..1	CodeableConcept	Use of the Group (and by implication, kind of members) Binding: GroupCode (extensible): A code that describes the kind of group, which usually dictates what kind if entities can be in the group.
quantity	Σ	0..1	unsignedInt	Number of members
managingEntity	Σ	0..1	Reference(Organization | RelatedPerson | Practitioner | PractitionerRole)	Entity that is the custodian of the Group's definition
combinationMethod	?!Σ	0..1	code	all-of | any-of | at-least | at-most | except-subset Binding: GroupCharacteristicCombination (required)
combinationThreshold		0..1	positiveInt	Provides the value of "n" when "at-least" or "at-most" codes are used
characteristic	Σ	0..*	BackboneElement	Include / Exclude group members by Trait
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
code	Σ	1..1	CodeableConcept	Kind of characteristic Binding: ExampleCharacteristicCodes (example): List of characteristics used to describe group members; e.g. gender, age, owner, location, etc.
value[x]	Σ	1..1		Value held by characteristic
valueCodeableConcept			CodeableConcept
valueBoolean			boolean
valueQuantity			Quantity
valueRange			Range
valueReference			Reference(Any)
valueUri			uri
valueExpression			Expression
exclude	Σ	1..1	boolean	Group includes or excludes
description		0..1	markdown	Natural language description of the characteristic
method		0..*	CodeableConcept	Method for how the characteristic value was determined Binding: DefinitionMethod (example)
determinedBy[x]		0..1		Defines the characteristic
determinedByReference			Reference(Device | DeviceDefinition | DeviceMetric)
determinedByExpression			Expression
offset	?!Σ	0..1	CodeableConcept	Reference point for comparison Binding: CharacteristicOffset (example)
instances[x]	C	0..1		Number of occurrences meeting the characteristic Constraints: grp-1
instancesUnsignedInt			unsignedInt
instancesRange			Range
duration[x]		0..1		Length of time in which the characteristic is met
durationDuration			Duration
durationRange			Range
period		0..1	Period	Period over which characteristic is tested
timing		0..*	RelativeTime	Timing in which the characteristic is determined
member		0..*	BackboneElement	Who or what is in group
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
entity		1..1	Reference(CareTeam | Device | Group | HealthcareService | Location | Organization | Patient | Practitioner | PractitionerRole | RelatedPerson | Specimen | Medication | Substance | BiologicallyDerivedProduct | NutritionProduct)	Reference to the group member
involvement		0..*	CodeableConcept	Code that describes how user is part of the group Binding: GroupInvolvement (example): A code that describes how a user is involved in the group
period		0..1	Period	Period member belonged to the group
inactive		0..1	boolean	If member is no longer in group
Documentation for this format

Terminology Bindings

Path	Status	Usage	ValueSet	Version	Source
Group.language	Base	required	All Languages	📍6.0.0-ballot3	FHIR Std.
Group.versionAlgorithm[x]	Base	extensible	Version Algorithm	📍6.0.0-ballot3	FHIR Std.
Group.status	Base	required	PublicationStatus	📍6.0.0-ballot3	FHIR Std.
Group.type	Base	required	Group Type	📍6.0.0-ballot3	FHIR Std.
Group.membership	Base	required	Group Membership Basis	📍6.0.0-ballot3	FHIR Std.
Group.code	Base	extensible	Group Code	📍6.0.0-ballot3	FHIR Std.
Group.combinationMethod	Base	required	Group Characteristic Combination	📍6.0.0-ballot3	FHIR Std.
Group.characteristic.​code	Base	example	Example Characterist ic Codes	📍6.0.0-ballot3	FHIR Std.
Group.characteristic.​method	Base	example	Definition Method	📍6.0.0-ballot3	FHIR Std.
Group.characteristic.​offset	Base	example	Characteristic Offset	📍6.0.0-ballot3	FHIR Std.
Group.member.involvement	Base	example	Group Involvement	📍6.0.0-ballot3	FHIR Std.

Constraints

Id	Grade	Path(s)	Description	Expression
cnl-1	warning	Group.url	URL should not contain | or # - these characters make processing canonical references problematic	exists() implies matches('^[^|# ]+$')
cnl-2	error	Group	Group.type SHALL be defined if Group.membership is either 'definitional' or 'enumerated'	Group.type.exists() or (Group.membership = 'conceptual')
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children	hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both	extension.exists() != value.exists()
grp-1	error	Group.characteristic.instances[x]	Ranges have to be positive	($this is Range) implies ((low.empty() or ((low.code.exists() or low.value.empty()) and (low.system.empty() or low.system = %ucum) and (low.code.empty() or low.code = '1') and (low.value.empty() or low.value.hasValue().not() or low.value.toString().contains('.').not()) and (low.value.empty() or low.value.hasValue().not() or low.value >= 0))) and (high.empty() or ((high.code.exists() or high.value.empty()) and (high.system.empty() or high.system = %ucum) and (high.code.empty() or high.code = '1') and (high.value.empty() or high.value.hasValue().not() or high.value.toString().contains('.').not()) and (high.value.empty() or high.value.hasValue().not() or high.value >= 0))))

Key Elements View

Name	Flags	Card.	Type	Description & Constraints    Filter: Bindings Constraints Obligations
Group	C	0..*	GroupR6	Group of multiple entities Interfaces Implemented: CanonicalResource Constraints: cnl-2
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
contained		0..*	Resource	Contained, inline Resources
Slices for extension				Content/Rules for all slices
extension:author		0..*	ContactDetail	Who authored the artifact URL: http://hl7.org/fhir/StructureDefinition/artifact-author
extension:citeAs		0..1	markdown	Citation for this Resource URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/cite-as
extension:relatesTo		0..*	(Complex)	Related artifact URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to
extension:RelatesToWithQuotation		0..*	(Complex)	Related artifact with quoted portion URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to-with-quotation
extension:characteristicExpression		0..1	Expression	Criteria for group membership URL: http://hl7.org/fhir/StructureDefinition/characteristicExpression
extension:publicationStatus		0..1	CodeableConcept	Publication status URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/artifact-publication-status Binding: Cited Artifact Status Type (preferred)
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored
status	?!Σ	0..1	code	draft | active | retired | unknown Binding: PublicationStatus (required): The lifecycle status of an artifact.
membership	Σ	1..1	code	definitional | conceptual | enumerated Binding: GroupMembershipBasis (required): The basis for membership in a group Required Pattern: enumerated
combinationMethod	?!Σ	0..1	code	all-of | any-of | at-least | at-most | except-subset Binding: GroupCharacteristicCombination (required)
Documentation for this format

Terminology Bindings

Path	Status	Usage	ValueSet	Version	Source
Group.status	Base	required	PublicationStatus	📍6.0.0-ballot3	FHIR Std.
Group.membership	Base	required	Group Membership Basis	📍6.0.0-ballot3	FHIR Std.
Group.combinationMethod	Base	required	Group Characteristic Combination	📍6.0.0-ballot3	FHIR Std.

Constraints

Id	Grade	Path(s)	Description	Expression
cnl-2	error	Group	Group.type SHALL be defined if Group.membership is either 'definitional' or 'enumerated'	Group.type.exists() or (Group.membership = 'conceptual')
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children	hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both	extension.exists() != value.exists()

Differential View

This structure is derived from GroupR6

Name	Flags	Card.	Type	Description & Constraints    Filter: Bindings Constraints Obligations
Group		0..*	GroupR6	Group of multiple entities Interfaces Implemented: CanonicalResource
membership		1..1	code	definitional | conceptual | enumerated Required Pattern: enumerated
Documentation for this format

Snapshot View

Name	Flags	Card.	Type	Description & Constraints    Filter: Bindings Constraints Obligations
Group	C	0..*	GroupR6	Group of multiple entities Interfaces Implemented: CanonicalResource Constraints: cnl-2
id	Σ	0..1	id	Logical id of this artifact
meta	Σ	0..1	Meta	Metadata about the resource
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
language		0..1	code	Language of the resource content Binding: AllLanguages (required): IETF language tag for a human language Additional Bindings Purpose CommonLanguages Starter
text		0..1	Narrative	Text summary of the resource, for human interpretation This profile does not constrain the narrative in regard to content, language, or traceability to data elements
contained		0..*	Resource	Contained, inline Resources
Slices for extension		0..*	Extension	Extension Slice: Unordered, Open by value:url
extension:author		0..*	ContactDetail	Who authored the artifact URL: http://hl7.org/fhir/StructureDefinition/artifact-author
extension:citeAs		0..1	markdown	Citation for this Resource URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/cite-as
extension:relatesTo		0..*	(Complex)	Related artifact URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to
extension:RelatesToWithQuotation		0..*	(Complex)	Related artifact with quoted portion URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/relates-to-with-quotation
extension:characteristicExpression		0..1	Expression	Criteria for group membership URL: http://hl7.org/fhir/StructureDefinition/characteristicExpression
extension:publicationStatus		0..1	CodeableConcept	Publication status URL: http://hl7.org/fhir/uv/ebm/StructureDefinition/artifact-publication-status Binding: Cited Artifact Status Type (preferred)
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored
url	ΣC	0..1	uri	Canonical identifier for this Group, represented as an absolute URI (globally unique) Constraints: cnl-1
identifier	Σ	0..*	Identifier	Business Identifier for this Group
version	Σ	0..1	string	Business version of the Group
versionAlgorithm[x]	Σ	0..1		How to compare versions Binding: VersionAlgorithm (extensible)
versionAlgorithmString			string
versionAlgorithmCoding			Coding
name	Σ	0..1	string	Label for Group
title	Σ	0..1	string	Name for this Group (human friendly)
status	?!Σ	0..1	code	draft | active | retired | unknown Binding: PublicationStatus (required): The lifecycle status of an artifact.
experimental	Σ	0..1	boolean	For testing only - never for real usage
date	Σ	0..1	dateTime	Date last changed
publisher	Σ	0..1	string	Name of the publisher/steward (organization or individual)
contact	Σ	0..*	ContactDetail	Contact details for the publisher
description		0..1	markdown	Natural language description of the group
useContext	Σ	0..*	UsageContext	The context that the content is intended to support
purpose		0..1	markdown	Why this Group is defined
copyright		0..1	markdown	Use and/or publishing restrictions
copyrightLabel		0..1	string	Copyright holder and year(s)
type	Σ	0..1	code	person | animal | practitioner | device | careteam | healthcareservice | location | organization | relatedperson | specimen | medication | substance | biologicallyDerivedProduct | nutritionProduct Binding: GroupType (required): Types of resources that are part of group.
membership	Σ	1..1	code	definitional | conceptual | enumerated Binding: GroupMembershipBasis (required): The basis for membership in a group Required Pattern: enumerated
code	Σ	0..1	CodeableConcept	Use of the Group (and by implication, kind of members) Binding: GroupCode (extensible): A code that describes the kind of group, which usually dictates what kind if entities can be in the group.
quantity	Σ	0..1	unsignedInt	Number of members
managingEntity	Σ	0..1	Reference(Organization | RelatedPerson | Practitioner | PractitionerRole)	Entity that is the custodian of the Group's definition
combinationMethod	?!Σ	0..1	code	all-of | any-of | at-least | at-most | except-subset Binding: GroupCharacteristicCombination (required)
combinationThreshold		0..1	positiveInt	Provides the value of "n" when "at-least" or "at-most" codes are used
characteristic	Σ	0..*	BackboneElement	Include / Exclude group members by Trait
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
code	Σ	1..1	CodeableConcept	Kind of characteristic Binding: ExampleCharacteristicCodes (example): List of characteristics used to describe group members; e.g. gender, age, owner, location, etc.
value[x]	Σ	1..1		Value held by characteristic
valueCodeableConcept			CodeableConcept
valueBoolean			boolean
valueQuantity			Quantity
valueRange			Range
valueReference			Reference(Any)
valueUri			uri
valueExpression			Expression
exclude	Σ	1..1	boolean	Group includes or excludes
description		0..1	markdown	Natural language description of the characteristic
method		0..*	CodeableConcept	Method for how the characteristic value was determined Binding: DefinitionMethod (example)
determinedBy[x]		0..1		Defines the characteristic
determinedByReference			Reference(Device | DeviceDefinition | DeviceMetric)
determinedByExpression			Expression
offset	?!Σ	0..1	CodeableConcept	Reference point for comparison Binding: CharacteristicOffset (example)
instances[x]	C	0..1		Number of occurrences meeting the characteristic Constraints: grp-1
instancesUnsignedInt			unsignedInt
instancesRange			Range
duration[x]		0..1		Length of time in which the characteristic is met
durationDuration			Duration
durationRange			Range
period		0..1	Period	Period over which characteristic is tested
timing		0..*	RelativeTime	Timing in which the characteristic is determined
member		0..*	BackboneElement	Who or what is in group
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
entity		1..1	Reference(CareTeam | Device | Group | HealthcareService | Location | Organization | Patient | Practitioner | PractitionerRole | RelatedPerson | Specimen | Medication | Substance | BiologicallyDerivedProduct | NutritionProduct)	Reference to the group member
involvement		0..*	CodeableConcept	Code that describes how user is part of the group Binding: GroupInvolvement (example): A code that describes how a user is involved in the group
period		0..1	Period	Period member belonged to the group
inactive		0..1	boolean	If member is no longer in group
Documentation for this format

Terminology Bindings

Path	Status	Usage	ValueSet	Version	Source
Group.language	Base	required	All Languages	📍6.0.0-ballot3	FHIR Std.
Group.versionAlgorithm[x]	Base	extensible	Version Algorithm	📍6.0.0-ballot3	FHIR Std.
Group.status	Base	required	PublicationStatus	📍6.0.0-ballot3	FHIR Std.
Group.type	Base	required	Group Type	📍6.0.0-ballot3	FHIR Std.
Group.membership	Base	required	Group Membership Basis	📍6.0.0-ballot3	FHIR Std.
Group.code	Base	extensible	Group Code	📍6.0.0-ballot3	FHIR Std.
Group.combinationMethod	Base	required	Group Characteristic Combination	📍6.0.0-ballot3	FHIR Std.
Group.characteristic.​code	Base	example	Example Characterist ic Codes	📍6.0.0-ballot3	FHIR Std.
Group.characteristic.​method	Base	example	Definition Method	📍6.0.0-ballot3	FHIR Std.
Group.characteristic.​offset	Base	example	Characteristic Offset	📍6.0.0-ballot3	FHIR Std.
Group.member.involvement	Base	example	Group Involvement	📍6.0.0-ballot3	FHIR Std.

Constraints

Id	Grade	Path(s)	Description	Expression
cnl-1	warning	Group.url	URL should not contain | or # - these characters make processing canonical references problematic	exists() implies matches('^[^|# ]+$')
cnl-2	error	Group	Group.type SHALL be defined if Group.membership is either 'definitional' or 'enumerated'	Group.type.exists() or (Group.membership = 'conceptual')
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children	hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both	extension.exists() != value.exists()
grp-1	error	Group.characteristic.instances[x]	Ranges have to be positive	($this is Range) implies ((low.empty() or ((low.code.exists() or low.value.empty()) and (low.system.empty() or low.system = %ucum) and (low.code.empty() or low.code = '1') and (low.value.empty() or low.value.hasValue().not() or low.value.toString().contains('.').not()) and (low.value.empty() or low.value.hasValue().not() or low.value >= 0))) and (high.empty() or ((high.code.exists() or high.value.empty()) and (high.system.empty() or high.system = %ucum) and (high.code.empty() or high.code = '1') and (high.value.empty() or high.value.hasValue().not() or high.value.toString().contains('.').not()) and (high.value.empty() or high.value.hasValue().not() or high.value >= 0))))

This structure is derived from GroupR6

Summary

Maturity: 1