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.

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.

Indicates whether the record for the group is available for use or is merely being retained for historical purposes.

Need to be able to mark a group record as not to be used because it was created in error or is otherwise no longer available (e.g. a herd that no longer exists).

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.
• '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.

Provides a specific type of resource the group includes; e.g. "cow", "syringe", etc.

This would generally be omitted for Person resources.

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

Used to identify the group in human communication.

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

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.

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.

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

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.

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.