Represents a defined collection of entities that may be discussed or acted upon collectively but which are not expected to act collectively, and are not formally or legally recognized; i.e. a collection of entities that isn't an Organization.

If both Group.characteristic and Group.member are present, then the members are the individuals who were found who met the characteristic. It's possible that there might be other candidate members who meet the characteristic and aren't (yet) in the list. All members SHALL have the listed characteristics.

An absolute URI that is used to identify this Group when it is referenced in a specification, model, design or an instance; also called its canonical identifier. This SHOULD be globally unique and SHOULD be a literal address at which an authoritative instance of this Group is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the Group is stored on different servers.

Allows the Group to be referenced by a single globally unique identifier.

Can be a urn:uuid: or a urn:oid: but real http: addresses are preferred. Multiple instances may share the same URL if they have a distinct version.

The determination of when to create a new version of a resource (same url, new version) vs. defining a new artifact is up to the author. Considerations for making this decision are found in Technical and Business Versions.

In some cases, the resource can no longer be found at the stated url, but the url itself cannot change. Implementations can use the meta.source element to indicate where the current master source of the resource can be found.

Business identifiers assigned to this participant by one of the applications involved. These identifiers remain constant as the resource is updated and propagates from server to server.

Allows identification of the group as it is known by various participating systems and in a way that remains consistent across servers.

Note: This is a business identifier, not a resource identifier (see discussion). It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types.

The identifier that is used to identify this version of the Group when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the Group author and is not expected to be globally unique. For example, it might be a timestamp (e.g. yyyymmdd) if a managed version is not available. There is also no expectation that versions can be placed in a lexicographical sequence without additional knowledge.

There may be different Groups that have the same url but different versions. The version can be appended to the url in a reference to allow a reference to a particular business version of the Group with the format [url]|[version]. The version SHOULD NOT contain a '#' - see Business Version.

Indicates the mechanism used to compare versions to determine which is more current.

If set as a string, this is a FHIRPath expression that has two additional context variables passed in - %version1 and %version2 and will return a negative number if version1 is newer, a positive number if version2 and a 0 if the version ordering can't be successfully be determined.

A label assigned to the group for human identification and communication.

Used to identify the group in human communication.

A short, descriptive, user-friendly title for the Group.

This name does not need to be machine-processing friendly and may contain punctuation, white-space, etc.

The current state of this Group.

Enables tracking the life-cycle of the content and filtering of Groups that are appropriate for use versus not.

A nominal state-transition diagram can be found in the Definition pattern documentation.

Unknown does not represent 'other' - one of the defined statuses must apply. Unknown is used when the authoring system is not sure what the current status is.

See guidance around (not) making local changes to elements here.

A Boolean value to indicate that this Group is authored for testing purposes (or education/evaluation/marketing) and is not intended for genuine usage.

Enables experimental content to be developed following the same lifecycle that would be used for a production-level Group.

Allows filtering of Groups that are appropriate for use versus not.

The date (and optionally time) when the Group was last significantly changed. The date must change when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the Group changes.

The date is often not tracked until the resource is published, but may be present on draft content. Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the Group. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.

See guidance around (not) making local changes to elements here.

The name of the organization or individual responsible for the release and ongoing maintenance of the Group.

Helps establish the "authority/credibility" of the Group. May also allow for contact.

Usually an organization but may be an individual. The publisher (or steward) of the Group is the organization or individual primarily responsible for the maintenance and upkeep of the Group. This is not necessarily the same individual or organization that developed and initially authored the content. The publisher is the primary point of contact for questions or issues with the Group. This item SHOULD be populated unless the information is available from context.

Contact details to assist a user in finding and communicating with the publisher.

May be a web site, an email address, a telephone number, etc.

See guidance around (not) making local changes to elements here.

Explanation of what the group represents and how it is intended to be used.

The content was developed with a focus and intent of supporting the contexts that are listed. These contexts may be general categories (gender, age, ...) or may be references to specific programs (insurance plans, studies, ...) and may be used to assist with indexing and searching for appropriate Groups.

Assist in searching for appropriate content.

When multiple useContexts are specified, there is no expectation that all or even any of the contexts apply.

Explanation of why this Group is needed and why it has been designed as it has.

This element does not describe the usage of the Group. Instead, it provides traceability of "why" the resource is either needed or "why" it is defined as it is. This may be used to point to source materials or specifications that drove the structure of this Group.

A copyright statement relating to the Group and/or its contents. Copyright statements are generally legal restrictions on the use and publishing of the Group.

Consumers must be able to determine any legal restrictions on the use of the Group and/or its content.

The short copyright declaration (e.g. (c) '2015 xyz organization' should be sent in the copyrightLabel element.

A short string (<50 characters), suitable for inclusion in a page footer that identifies the copyright holder, effective period, and optionally whether rights are resctricted. (e.g. 'All rights reserved', 'Some rights reserved').

Defines the content expected to be rendered in all representations of the artifact.

The (c) symbol should NOT be included in this string. It will be added by software when rendering the notation. Full details about licensing, restrictions, warrantees, etc. goes in the more general 'copyright' element.

Identifies the broad classification of the kind of resources the group includes.

Identifies what type of resources the group is made up of.

Group members SHALL be of the appropriate resource type (Patient for person or animal; or Practitioner, PractitionerRole, Device, CareTeam, HealthcareService, Location, Organization, RelatedPerson, or Specimen for the other types.), or a Group of the resources of the appropriate type.

Basis for membership in the Group:

• 'definitional': The Group.characteristics specified are both necessary and sufficient to determine membership. All entities that meet the criteria are considered to be members of the group, whether referenced by the group or not. If members are present, they are individuals that happen to be known as meeting the Group.characteristics. The list cannot be presumed to be complete.
• 'conceptual': The Group.characteristics specified are both necessary and sufficient to determine membership. The 'conceptual' Group is a 'definitional' Group in which the Group.type is not bound to FHIR types.
• 'enumerated': The Group.characteristics are necessary but not sufficient to determine membership. Membership is determined by being listed as one of the Group.member.

There are use-cases for groups that define specific collections of individuals, and other groups that define "types" of intended individuals. The requirements for both kinds of groups are similar, so we use a single resource, distinguished by this element.

A code that describes the use of the group. The use of the group usually dictates what kind of entities can be members of the group.

The types of entities that can be members needs to align with Group.type

A count of the number of resource instances that are part of the group.

Group size is a common defining characteristic.

Note that the quantity may be less than the number of members if some of the members are not active.

Entity responsible for defining and maintaining Group characteristics and/or registered members.

This does not strictly align with ownership of a herd or flock, but may suffice to represent that relationship in simple cases. More complex cases will require an extension.

Used to specify how two or more characteristics are combined.

Provides the value of "n" when "at-least" or "at-most" codes are used for combinationMethod.

Identifies traits whose presence r absence is shared by members of the group.

Needs to be a generic mechanism for identifying what individuals can be part of a group.

All the identified characteristics must be true for an entity to a member of the group.

A code that identifies the kind of trait being asserted.

Need a formal way of identifying the characteristic being described.

The value of the trait that holds (or does not hold - see 'exclude') for members of the group.

The value of the characteristic is what determines group membership.

For Range, it means members of the group have a value that falls somewhere within the specified range.

If true, indicates the characteristic is one that is NOT held by members of the group.

Sometimes group membership is determined by characteristics not possessed.

This is labeled as "Is Modifier" because applications cannot wrongly include excluded members as included or vice versa.

A short, natural language description of the characteristic that could be used to communicate the criteria to an end-user.

Need to be able to describe characteristics in natural language so that end users can understand the criteria.

Method for how the characteristic value was determined.

Defines the characteristic (without using type and value) by either a Reference or an Expression.

The value of the characteristic is what determines group membership.

Defines the reference point for comparison when other than 0.

Number of occurrences meeting the characteristic.

Length of time in which the characteristic is met.

The period over which the characteristic is tested; e.g. the patient had an operation during the month of June.

Timing in which the characteristic is determined.

Identifies the resource instances that are members of the group.

Often the only thing of interest about a group is "who's in it".

A reference to the entity that is a member of the group. Must be consistent with Group.type. If the entity is another group, then the type must be the same.

A code that describes how a user is involved in the group. Some groups (e.g. exposure-group) typically don't have variance between members, or it is not tracked, while for other groups (e.g. family, household) this may be meaningful.

The period that the member was in the group, if known.

Need to track who was in a group at a particular time.

A flag to indicate that the member is no longer in the group, but previously may have been a member.

Sometimes you don't know when someone stopped being in a group, but not when.