• pattern @ type

• value @ url

• value @ url
• value @ value.ofType(Identifier).type

• pattern @ type

• pattern @ type

A record of an event made for purposes of maintaining a security log. Typical uses include detection of intrusion attempts and monitoring for inappropriate usage.

Based on IHE-ATNA.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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 is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Identifier for a family of the event. For example, a menu item, program, rule, policy, function code, application name or URL. It identifies the performed function.

This identifies the performed function. For "Execute" Event Action Code audit records, this identifies the application function performed.

The time when the event was recorded.

In a distributed system, some sort of common time base (e.g. an NTP [RFC1305] server) is a good implementation tactic.

This ties an event to a specific date and time. Security audits typically require a consistent time base (e.g. UTC), to eliminate time-zone issues arising from geographical distribution.

An actor taking an active role in the event or activity that is logged.

Several agents may be associated (i.e. have some responsibility for an activity) with an event or activity.

For example, an activity may be initiated by one user for other users or involve more than one user. However, only one user may be the initiator/requestor for the activity.

An agent can be a person, an organization, software, device, or other actors that may be ascribed responsibility.

• pattern @ type

An Extension

• value @ url

The assuranceLevel element carries various types of Assurance level. May be an Identity Assurance (IAL), an Authentication Assurance Level (AAL), a Federation Assurance Level (FAL), or other.

In SAML this is defined to be carried in the saml:AuthnContextClassRef, but may be carried elsewhere based on the use-case and profiling of SAML.

The Vocabulary is not defined here. Some sources of vocabulary:

• HL7 v3 Security Trust Assurance ValueSet. These include ISO-7498-2, NIST 800-63-1, and NIST-800-63-2.
• idmanagement.gov published on login.gov
  • this is defined to be carried in the saml:AuthnContextClassRef
• OASIS Authentication Context for SAML
• An example of a customized and purpose defined small set of codes can be found in the HL7 SMART Health Cards defines a valueset

Carries other identifiers are known for an agent.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Indicator that the user is or is not the requestor, or initiator, for the event being audited.

There can only be one initiator. If the initiator is not clear, then do not choose any one agent as the initiator.

This value is used to distinguish between requestor-users and recipient-users. For example, one person may initiate a report-output to be sent to another user.

An actor taking an active role in the event or activity that is logged.

Several agents may be associated (i.e. have some responsibility for an activity) with an event or activity.

For example, an activity may be initiated by one user for other users or involve more than one user. However, only one user may be the initiator/requestor for the activity.

An agent can be a person, an organization, software, device, or other actors that may be ascribed responsibility.

An Extension

• value @ url
• value @ value.ofType(Identifier).type

The assuranceLevel element carries various types of Assurance level. May be an Identity Assurance (IAL), an Authentication Assurance Level (AAL), a Federation Assurance Level (FAL), or other.

In SAML this is defined to be carried in the saml:AuthnContextClassRef, but may be carried elsewhere based on the use-case and profiling of SAML.

The Vocabulary is not defined here. Some sources of vocabulary:

• HL7 v3 Security Trust Assurance ValueSet. These include ISO-7498-2, NIST 800-63-1, and NIST-800-63-2.
• idmanagement.gov published on login.gov
  • this is defined to be carried in the saml:AuthnContextClassRef
• OASIS Authentication Context for SAML
• An example of a customized and purpose defined small set of codes can be found in the HL7 SMART Health Cards defines a valueset

Carries other identifiers are known for an agent.

Carries other identifiers are known for an agent.

An Extension

• value @ url

Source of the definition for the extension code - a logical name or a URL.

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.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

The purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

Allows users to make use of identifiers when the identifier system is not known.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

Carries other identifiers are known for an agent.

An Extension

• value @ url

Source of the definition for the extension code - a logical name or a URL.

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.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

The purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

Allows users to make use of identifiers when the identifier system is not known.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

Carries other identifiers are known for an agent.

An Extension

• value @ url

Source of the definition for the extension code - a logical name or a URL.

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.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

The purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

Allows users to make use of identifiers when the identifier system is not known.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Specification of the participation type the user plays when performing the event.

The security role that the user was acting under, that come from local codes defined by the access control security system (e.g. RBAC, ABAC) used in the local context.

Should be roles relevant to the event. Should not be an exhaustive list of roles.

This value ties an audited event to a user's role(s). It is an optional value that might be used to group events for analysis by user functional role categories.

Reference to who this agent is that was involved in the event.

Where a User ID is available it will go into who.identifier.

This field ties an audit event to a specific resource or identifier.

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

The purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

Identifier.system is always case sensitive.

There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

Alternative agent Identifier. For a human, this should be a user identifier text string from authentication system. This identifier would be one known to a common authentication system (e.g. single sign-on), if available.

In some situations, a human user may authenticate with one identity but, to access a specific application system, may use a synonymous identify. For example, some "single sign on" implementations will do this. The alternative identifier would then be the original identify used for authentication, and the User ID is the one known to and used by the application.

Indicator that the user is or is not the requestor, or initiator, for the event being audited.

There can only be one initiator. If the initiator is not clear, then do not choose any one agent as the initiator.

This value is used to distinguish between requestor-users and recipient-users. For example, one person may initiate a report-output to be sent to another user.

The policy or plan that authorized the activity being recorded. Typically, a single activity may have multiple applicable policies, such as patient consent, guarantor funding, etc. The policy would also indicate the security token used.

For example: Where an OAuth token authorizes, the unique identifier from the OAuth token is placed into the policy element Where a policy engine (e.g. XACML) holds policy logic, the unique policy identifier is placed into the policy element.

This value is used retrospectively to determine the authorization policies.

Type of media involved. Used when the event is about exporting/importing onto media.

Usually, this is used instead of specifying a network address. This field is not used for Media Id (i.e. the serial number of a CD).

Logical network location for application activity, if the activity has a network location.

The reason (purpose of use), specific to this agent, that was used during the event being recorded.

Use AuditEvent.agent.purposeOfUse when you know that is specific to the agent, otherwise use AuditEvent.purposeOfEvent. For example, during a machine-to-machine transfer it might not be obvious to the audit system who caused the event, but it does know why.

An actor taking an active role in the event or activity that is logged.

Several agents may be associated (i.e. have some responsibility for an activity) with an event or activity.

For example, an activity may be initiated by one user for other users or involve more than one user. However, only one user may be the initiator/requestor for the activity.

An agent can be a person, an organization, software, device, or other actors that may be ascribed responsibility.

The assuranceLevel element carries various types of Assurance level. May be an Identity Assurance (IAL), an Authentication Assurance Level (AAL), a Federation Assurance Level (FAL), or other.

In SAML this is defined to be carried in the saml:AuthnContextClassRef, but may be carried elsewhere based on the use-case and profiling of SAML.

The Vocabulary is not defined here. Some sources of vocabulary:

• HL7 v3 Security Trust Assurance ValueSet. These include ISO-7498-2, NIST 800-63-1, and NIST-800-63-2.
• idmanagement.gov published on login.gov
  • this is defined to be carried in the saml:AuthnContextClassRef
• OASIS Authentication Context for SAML
• An example of a customized and purpose defined small set of codes can be found in the HL7 SMART Health Cards defines a valueset

Carries other identifiers are known for an agent.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Specification of the participation type the user plays when performing the event.

The security role that the user was acting under, that come from local codes defined by the access control security system (e.g. RBAC, ABAC) used in the local context.

Should be roles relevant to the event. Should not be an exhaustive list of roles.

This value ties an audited event to a user's role(s). It is an optional value that might be used to group events for analysis by user functional role categories.

Reference to who this agent is that was involved in the event.

Where a User ID is available it will go into who.identifier.

This field ties an audit event to a specific resource or identifier.

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

The purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

Alternative agent Identifier. For a human, this should be a user identifier text string from authentication system. This identifier would be one known to a common authentication system (e.g. single sign-on), if available.

In some situations, a human user may authenticate with one identity but, to access a specific application system, may use a synonymous identify. For example, some "single sign on" implementations will do this. The alternative identifier would then be the original identify used for authentication, and the User ID is the one known to and used by the application.

Human-meaningful name for the agent.

The User ID and Authorization User ID may be internal or otherwise obscure values. This field assists the auditor in identifying the actual user.

Indicator that the user is or is not the requestor, or initiator, for the event being audited.

There can only be one initiator. If the initiator is not clear, then do not choose any one agent as the initiator.

This value is used to distinguish between requestor-users and recipient-users. For example, one person may initiate a report-output to be sent to another user.

Where the event occurred.

The policy or plan that authorized the activity being recorded. Typically, a single activity may have multiple applicable policies, such as patient consent, guarantor funding, etc. The policy would also indicate the security token used.

For example: Where an OAuth token authorizes, the unique identifier from the OAuth token is placed into the policy element Where a policy engine (e.g. XACML) holds policy logic, the unique policy identifier is placed into the policy element.

This value is used retrospectively to determine the authorization policies.

Type of media involved. Used when the event is about exporting/importing onto media.

Usually, this is used instead of specifying a network address. This field is not used for Media Id (i.e. the serial number of a CD).

Logical network location for application activity, if the activity has a network location.

The reason (purpose of use), specific to this agent, that was used during the event being recorded.

Use AuditEvent.agent.purposeOfUse when you know that is specific to the agent, otherwise use AuditEvent.purposeOfEvent. For example, during a machine-to-machine transfer it might not be obvious to the audit system who caused the event, but it does know why.

An actor taking an active role in the event or activity that is logged.

Several agents may be associated (i.e. have some responsibility for an activity) with an event or activity.

For example, an activity may be initiated by one user for other users or involve more than one user. However, only one user may be the initiator/requestor for the activity.

An agent can be a person, an organization, software, device, or other actors that may be ascribed responsibility.

The assuranceLevel element carries various types of Assurance level. May be an Identity Assurance (IAL), an Authentication Assurance Level (AAL), a Federation Assurance Level (FAL), or other.

In SAML this is defined to be carried in the saml:AuthnContextClassRef, but may be carried elsewhere based on the use-case and profiling of SAML.

The Vocabulary is not defined here. Some sources of vocabulary:

• HL7 v3 Security Trust Assurance ValueSet. These include ISO-7498-2, NIST 800-63-1, and NIST-800-63-2.
• idmanagement.gov published on login.gov
  • this is defined to be carried in the saml:AuthnContextClassRef
• OASIS Authentication Context for SAML
• An example of a customized and purpose defined small set of codes can be found in the HL7 SMART Health Cards defines a valueset

Carries other identifiers are known for an agent.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Specification of the participation type the user plays when performing the event.

The security role that the user was acting under, that come from local codes defined by the access control security system (e.g. RBAC, ABAC) used in the local context.

Should be roles relevant to the event. Should not be an exhaustive list of roles.

This value ties an audited event to a user's role(s). It is an optional value that might be used to group events for analysis by user functional role categories.

Reference to who this agent is that was involved in the event.

Where a User ID is available it will go into who.identifier.

This field ties an audit event to a specific resource or identifier.

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

Alternative agent Identifier. For a human, this should be a user identifier text string from authentication system. This identifier would be one known to a common authentication system (e.g. single sign-on), if available.

In some situations, a human user may authenticate with one identity but, to access a specific application system, may use a synonymous identify. For example, some "single sign on" implementations will do this. The alternative identifier would then be the original identify used for authentication, and the User ID is the one known to and used by the application.

Human-meaningful name for the agent.

The User ID and Authorization User ID may be internal or otherwise obscure values. This field assists the auditor in identifying the actual user.

Indicator that the user is or is not the requestor, or initiator, for the event being audited.

There can only be one initiator. If the initiator is not clear, then do not choose any one agent as the initiator.

This value is used to distinguish between requestor-users and recipient-users. For example, one person may initiate a report-output to be sent to another user.

Where the event occurred.

The policy or plan that authorized the activity being recorded. Typically, a single activity may have multiple applicable policies, such as patient consent, guarantor funding, etc. The policy would also indicate the security token used.

For example: Where an OAuth token authorizes, the unique identifier from the OAuth token is placed into the policy element Where a policy engine (e.g. XACML) holds policy logic, the unique policy identifier is placed into the policy element.

This value is used retrospectively to determine the authorization policies.

Type of media involved. Used when the event is about exporting/importing onto media.

Usually, this is used instead of specifying a network address. This field is not used for Media Id (i.e. the serial number of a CD).

Logical network location for application activity, if the activity has a network location.

The reason (purpose of use), specific to this agent, that was used during the event being recorded.

Use AuditEvent.agent.purposeOfUse when you know that is specific to the agent, otherwise use AuditEvent.purposeOfEvent. For example, during a machine-to-machine transfer it might not be obvious to the audit system who caused the event, but it does know why.

The system that is reporting the event.

Since multi-tier, distributed, or composite applications make source identification ambiguous, this collection of fields may repeat for each application or process actively involved in the event. For example, multiple value-sets can identify participating web servers, application processes, and database server threads in an n-tier distributed application. Passive event participants (e.g. low-level network transports) need not be identified.

The event is reported by one source.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Identifier of the source where the event was detected.

This field ties the event to a specific source system. It may be used to group events for analysis according to where the event was detected.

Specific instances of data or objects that have been accessed.

Required unless the values for event identification, agent identification, and audit source identification are sufficient to document the entire auditable event. Because events may have more than one entity, this group can be a repeating set of values.

The event may have other entities involved.

• pattern @ type

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Specific instances of data or objects that have been accessed.

Required unless the values for event identification, agent identification, and audit source identification are sufficient to document the entire auditable event. Because events may have more than one entity, this group can be a repeating set of values.

The event may have other entities involved.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Identifies a specific instance of the entity. The reference should be version specific.

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

The type of the object that was involved in this audit event.

This value is distinct from the user's role or any user relationship to the entity.

To describe the object being acted upon. In addition to queries on the subject of the action in an auditable event, it is also important to be able to query on the object type for the action.

Tagged value pairs for conveying additional information about the entity.

Implementation-defined data about specific details of the object accessed or used.

• pattern @ type

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

The type of extra detail provided in the value.

The value of the extra detail.

The value can be string when known to be a string, else base64 encoding should be used to protect binary or undefined content. The meaning and secondary-encoding of the content of base64 encoded blob is specific to the AuditEvent.type, AuditEvent.subtype, AuditEvent.entity.type, and AuditEvent.entity.role. The base64 is a general-use and safe container for event specific data blobs regardless of the encoding used by the transaction being recorded. An AuditEvent consuming application must understand the event it is consuming and the formats used by the event. For example if auditing an Oracle network database access, the Oracle formats must be understood as they will be simply encoded in the base64binary blob.

Should not duplicate the entity value unless absolutely necessary.

Tagged value pairs for conveying additional information about the entity.

Implementation-defined data about specific details of the object accessed or used.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

The type of extra detail provided in the value.

The value of the extra detail.

The value can be string when known to be a string, else base64 encoding should be used to protect binary or undefined content. The meaning and secondary-encoding of the content of base64 encoded blob is specific to the AuditEvent.type, AuditEvent.subtype, AuditEvent.entity.type, and AuditEvent.entity.role. The base64 is a general-use and safe container for event specific data blobs regardless of the encoding used by the transaction being recorded. An AuditEvent consuming application must understand the event it is consuming and the formats used by the event. For example if auditing an Oracle network database access, the Oracle formats must be understood as they will be simply encoded in the base64binary blob.

Should not duplicate the entity value unless absolutely necessary.

Tagged value pairs for conveying additional information about the entity.

Implementation-defined data about specific details of the object accessed or used.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

The type of extra detail provided in the value.