Slicing Note: The rules on this element (including its children) apply to all the slices, but are not repeated in them

requested: the notification or call is planned, its moment has not come yet. in-progress: the notification is due and is being sent. ready: the care provider should call the patient. completed: the notification was sent, or a client marked it completed. failed: a client marked the notification failed, or the due date of the call passed. cancelled: the notification or call is no longer needed, for example because the questionnaire was already completed, or a client cancelled the notification.

A task to be performed.

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.

An Extension

Slicing Note: The rules on this element (including its children) apply to all the slices, but are not repeated in them

The UUID of the program task this activity or Task represents

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.

BasedOn refers to a higher-level authorization that triggered the creation of the task. It references a "request" resource such as a ServiceRequest, MedicationRequest, ServiceRequest, CarePlan, etc. which is distinct from the "request" resource the task is seeking to fulfill. This latter resource is referenced by FocusOn. For example, based on a ServiceRequest (= BasedOn), a task is created to fulfill a procedureRequest ( = FocusOn ) to collect a specimen from a patient.

The current status of the task.

requested: the notification or call is planned, its moment has not come yet. in-progress: the notification is due and is being sent. ready: the care provider should call the patient. completed: the notification was sent, or a client marked it completed. failed: a client marked the notification failed, or the due date of the call passed. cancelled: the notification or call is no longer needed, for example because the questionnaire was already completed, or a client cancelled the notification.

These states enable coordination of task status with off-the-shelf workflow solutions that support automation of tasks.

Indicates the "level" of actionability associated with the Task, i.e. i+R[9]Cs this a proposed task, a planned task, an actionable task, etc.

This element is immutable. Proposed tasks, planned tasks, etc. must be distinct instances.

In most cases, Tasks will have an intent of "order".

Distinguishes whether the task is a proposal, plan or full order.

A name or code (or both) briefly describing what the task involves.

The title (eg "My Tasks", "Outstanding Tasks for Patient X") should go into the code.

A free-text description of what is to be performed.

The request being actioned or the resource being manipulated by this task.

If multiple resources need to be manipulated, use sub-tasks. (This ensures that status can be tracked independently for each referenced resource.).

Used to identify the thing to be done.

The entity who benefits from the performance of the service specified in the task (e.g., the patient).

Used to track tasks outstanding for a beneficiary. Do not use to track the task owner or creator (see owner and creator respectively). This can also affect access control.

Identifies the time action was first taken against the task (start) and/or the time final action was taken against the task prior to marking it as completed (end).

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

The date and time this task was created.

Most often used along with lastUpdated to track duration of task to supporting monitoring and management.

The creator of the task.

Identifies who created this task. May be used by access control mechanisms (e.g., to ensure that only the creator can cancel a task).

Individual organization or Device currently responsible for task execution.

Tasks may be created with an owner not yet identified.

Identifies who is expected to perform this task.

If the Task.focus is a request resource and the task is seeking fulfillment (i.e. is asking for the request to be actioned), this element identifies any limitations on what parts of the referenced request should be actioned.

Sometimes when fulfillment is sought, you don't want full fulfillment.

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.

Over what time-period is fulfillment sought.

Note that period.high is the due date representing the time by which the task should be completed.

E.g. order that authorizes 1 year's services. Fulfillment is sought for next 3 months.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

A task to be performed.

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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.

The version specific identifier, as it appears in the version portion of the URL. This value changes when the resource is created, updated, or deleted.

The server assigns this value, and ignores what the client specifies, except in the case that the server is imposing version integrity on updates/deletes.

When the resource last changed - e.g. when the version changed.

This value is always populated except when the resource is first being created. The server / resource manager sets this value; what a client provides is irrelevant. This is equivalent to the HTTP Last-Modified and SHOULD have the same value on a read interaction.

A uri that identifies the source system of the resource. This provides a minimal amount of Provenance information that can be used to track or differentiate the source of information in the resource. The source may identify another FHIR server, document, message, database, etc.

In the provenance resource, this corresponds to Provenance.entity.what[x]. The exact use of the source (and the implied Provenance.entity.role) is left to implementer discretion. Only one nominated source is allowed; for additional provenance details, a full Provenance resource should be used.

This element can be used to indicate where the current master source of a resource that has a canonical URL if the resource is no longer hosted at the canonical URL.

A list of profiles (references to StructureDefinition resources) that this resource claims to conform to. The URL is a reference to StructureDefinition.url.

It is up to the server and/or other infrastructure of policy to determine whether/how these claims are verified and/or updated over time. The list of profile URLs is a set.

Security labels applied to this resource. These tags connect specific resources to the overall security policy and infrastructure.

The security labels can be updated without changing the stated version of the resource. The list of security labels is a set. Uniqueness is based the system/code, and version and display are ignored.

Security Labels from the Healthcare Privacy and Security Classification System.

Tags applied to this resource. Tags are intended to be used to identify and relate resources to process and workflow, and applications are not required to consider the tags when interpreting the meaning of a resource.

The tags can be updated without changing the stated version of the resource. The list of tags is a set. Uniqueness is based the system/code, and version and display are ignored.

Codes that represent various types of tags, commonly workflow-related; e.g. "Needs review by Dr. Jones".

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.

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

A human language.

A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

An Extension

Slicing Note: The rules on this element (including its children) apply to all the slices, but are not repeated in them

The UUID of the program task this activity or Task represents

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.

The business identifier for this task.

The URL pointing to a FHIR-defined protocol, guideline, orderset or other definition that is adhered to in whole or in part by this Task.

Enables a formal definition of how he task is to be performed, enabling automation.

The URL pointing to an externally maintained protocol, guideline, orderset or other definition that is adhered to in whole or in part by this Task.

Enables a formal definition of how he task is to be performed (e.g. using BPMN, BPEL, XPDL or other formal notation to be associated with a task), enabling automation.

BasedOn refers to a higher-level authorization that triggered the creation of the task. It references a "request" resource such as a ServiceRequest, MedicationRequest, ServiceRequest, CarePlan, etc. which is distinct from the "request" resource the task is seeking to fulfill. This latter resource is referenced by FocusOn. For example, based on a ServiceRequest (= BasedOn), a task is created to fulfill a procedureRequest ( = FocusOn ) to collect a specimen from a patient.

An identifier that links together multiple tasks and other requests that were created in the same context.

Billing and/or reporting can be linked to whether multiple requests were created as a single unit.

Task that this particular task is part of.

This should usually be 0..1.

Allows tasks to be broken down into sub-steps (and this division can occur independent of the original task).

The current status of the task.

requested: the notification or call is planned, its moment has not come yet. in-progress: the notification is due and is being sent. ready: the care provider should call the patient. completed: the notification was sent, or a client marked it completed. failed: a client marked the notification failed, or the due date of the call passed. cancelled: the notification or call is no longer needed, for example because the questionnaire was already completed, or a client cancelled the notification.

These states enable coordination of task status with off-the-shelf workflow solutions that support automation of tasks.

An explanation as to why this task is held, failed, was refused, etc.

This applies to the current status. Look at the history of the task to see reasons for past statuses.

Codes to identify the reason for current status. These will typically be specific to a particular workflow.

Contains business-specific nuances of the business state.

The domain-specific business-contextual sub-state of the task. For example: "Blood drawn", "IV inserted", "Awaiting physician signature", etc.

There's often a need to track substates of a task - this is often variable by specific workflow implementation.

Indicates the "level" of actionability associated with the Task, i.e. i+R[9]Cs this a proposed task, a planned task, an actionable task, etc.

This element is immutable. Proposed tasks, planned tasks, etc. must be distinct instances.

In most cases, Tasks will have an intent of "order".

Distinguishes whether the task is a proposal, plan or full order.

Indicates how quickly the Task should be addressed with respect to other requests.

The task's priority.

Used to identify the service level expected while performing a task.

A name or code (or both) briefly describing what the task involves.

The title (eg "My Tasks", "Outstanding Tasks for Patient X") should go into the code.

A free-text description of what is to be performed.

The request being actioned or the resource being manipulated by this task.

If multiple resources need to be manipulated, use sub-tasks. (This ensures that status can be tracked independently for each referenced resource.).

Used to identify the thing to be done.

The entity who benefits from the performance of the service specified in the task (e.g., the patient).

Used to track tasks outstanding for a beneficiary. Do not use to track the task owner or creator (see owner and creator respectively). This can also affect access control.

The healthcare event (e.g. a patient and healthcare provider interaction) during which this task was created.

For some tasks it may be important to know the link between the encounter the task originated within.

Identifies the time action was first taken against the task (start) and/or the time final action was taken against the task prior to marking it as completed (end).

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

The date and time this task was created.

Most often used along with lastUpdated to track duration of task to supporting monitoring and management.

The date and time of last modification to this task.

Used along with history to track task activity and time in a particular task state. This enables monitoring and management.

The creator of the task.

Identifies who created this task. May be used by access control mechanisms (e.g., to ensure that only the creator can cancel a task).

The kind of participant that should perform the task.

The type(s) of task performers allowed.

Use to distinguish tasks on different activity queues.

Individual organization or Device currently responsible for task execution.

Tasks may be created with an owner not yet identified.

Identifies who is expected to perform this task.

Principal physical location where the this task is performed.

Ties the event to where the records are likely kept and provides context around the event occurrence (e.g. if it occurred inside or outside a dedicated healthcare setting).

A description or code indicating why this task needs to be performed.

This should only be included if there is no focus or if it differs from the reason indicated on the focus.

Indicates why the task is needed. E.g. Suspended because patient admitted to hospital.

A resource reference indicating why this task needs to be performed.

Tasks might be justified based on an Observation, a Condition, a past or planned procedure, etc. This should only be included if there is no focus or if it differs from the reason indicated on the focus. Use the CodeableConcept text element in Task.reasonCode if the data is free (uncoded) text.

Insurance plans, coverage extensions, pre-authorizations and/or pre-determinations that may be relevant to the Task.

Free-text information captured about the task as it progresses.

Links to Provenance records for past versions of this Task that identify key state transitions or updates that are likely to be relevant to a user looking at the current version of the task.

This element does not point to the Provenance associated with the current version of the resource - as it would be created after this version existed. The Provenance for the current version can be retrieved with a _revinclude.

If the Task.focus is a request resource and the task is seeking fulfillment (i.e. is asking for the request to be actioned), this element identifies any limitations on what parts of the referenced request should be actioned.

Sometimes when fulfillment is sought, you don't want full fulfillment.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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.

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.

Indicates the number of times the requested action should occur.

E.g. order that requests monthly lab tests, fulfillment is sought for 1.

Over what time-period is fulfillment sought.

Note that period.high is the due date representing the time by which the task should be completed.

E.g. order that authorizes 1 year's services. Fulfillment is sought for next 3 months.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

For requests that are targeted to more than on potential recipient/target, for whom is fulfillment sought?

Additional information that may be needed in the execution of the task.

Resources and data used to perform the task. This data is used in the business logic of task execution, and is stored separately because it varies between workflows.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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.

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.

A code or description indicating how the input is intended to be used as part of the task execution.

If referencing a BPMN workflow or Protocol, the "system" is the URL for the workflow definition and the code is the "name" of the required input.

Codes to identify types of input parameters. These will typically be specific to a particular workflow. E.g. "Comparison source", "Applicable consent", "Concomitent Medications", etc.

Inputs are named to enable task automation to bind data and pass it from one task to the next.

The value of the input parameter as a basic type.

Outputs produced by the Task.

Resources and data produced during the execution the task. This data is generated by the business logic of task execution, and is stored separately because it varies between workflows.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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.

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 name of the Output parameter.

Codes to identify types of input parameters. These will typically be specific to a particular workflow. E.g. "Identified issues", "Preliminary results", "Filler order", "Final results", etc.

Outputs are named to enable task automation to bind data and pass it from one task to the next.

The value of the Output parameter as a basic type.

Task outputs can take any form.