R4 Ballot #2 (Mixed Normative/Trial use)

This page is part of the FHIR Specification (v3.5.0: R4 Ballot #2). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4 R3 R2

FHIR Infrastructure Work GroupMaturity Level: 3 Trial Use Compartments: Not linked to any defined compartments

Detailed Descriptions for the elements in the Questionnaire resource.

Questionnaire
Element IdQuestionnaire
Definition

A structured set of questions intended to guide the collection of answers from end-users. Questionnaires provide detailed control over order, presentation, phraseology and grouping to allow coherent, consistent data collection.

Control1..1
TypeDomainResource
Requirements

To support structured, hierarchical registration of data gathered using digital forms and other questionnaires. Questionnaires provide greater control over presentation and allow capture of data in a domain-independent way (i.e. capturing information that would otherwise require multiple distinct types of resources).

Alternate NamesForm; CRF; Survey
Invariants
Defined on this element
que-0Warning Name should be usable as an identifier for the module by machine processing applications such as code generationname.matches('[A-Z]([A-Za-z0-9_]){0,254}')
que-2Rule The link ids for groups and questions must be unique within the questionnairedescendants().linkId.isDistinct()
Questionnaire.url
Element IdQuestionnaire.url
Definition

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

Control0..1
Typeuri
Requirements

… This is the id that will be used to link a QuestionnaireResponse to the Questionnaire the response is for.

Summarytrue
Comments

The name of the referenced questionnaire can be conveyed using the http://hl7.org/fhir/StructureDefinition/display extension.

Questionnaire.identifier
Element IdQuestionnaire.identifier
Definition

A formal identifier that is used to identify this questionnaire when it is represented in other formats, or referenced in a specification, model, design or an instance.

NoteThis is a business identifer, not a resource identifier (see discussion)
Control0..*
TypeIdentifier
Requirements

Allows externally provided and/or usable business identifiers to be easily associated with the module.

Summarytrue
Comments

Typically, this is used for identifiers that can go in an HL7 V3 II (instance identifier) data type, and can then identify this questionnaire outside of FHIR, where it is not possible to use the logical URI.

Questionnaire.version
Element IdQuestionnaire.version
Definition

The identifier that is used to identify this version of the questionnaire when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the questionnaire author and is not expected to be globally unique. For example, it might be a timestamp (e.g. yyyymmdd) if a managed version is not available. There is also no expectation that versions can be placed in a lexicographical sequence.

NoteThis is a business versionId, not a resource version id (see discussion)
Control0..1
Typestring
Summarytrue
Comments

There may be different questionnaire instances that have the same identifier but different versions. The version can be appended to the url in a reference to allow a reference to a particular business version of the questionnaire with the format [url]|[version].

Questionnaire.name
Element IdQuestionnaire.name
Definition

A natural language name identifying the questionnaire. This name should be usable as an identifier for the module by machine processing applications such as code generation.

Control0..1
Typestring
Requirements

Support human navigation and code generation.

Summarytrue
Comments

The name is not expected to be globally unique. The name should be a simple alphanumeric type name to ensure that it is machine-processing friendly.

Invariants
Affect this element
inv-0Warning Name should be usable as an identifier for the module by machine processing applications such as code generationname.matches('[A-Z]([A-Za-z0-9_]){0,254}')
Questionnaire.title
Element IdQuestionnaire.title
Definition

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

Control0..1
Typestring
Summarytrue
Comments

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

Questionnaire.derivedFrom
Element IdQuestionnaire.derivedFrom
Definition

The URL of a Questionnaire that this Questionnaire is based on.

Control0..*
Typecanonical(Questionnaire)
Requirements

Allows a Questionnaire to be created based on another Questionnaire.

Questionnaire.status
Element IdQuestionnaire.status
Definition

The status of this questionnaire. Enables tracking the life-cycle of the content.

Control1..1
Terminology BindingPublicationStatus (Required)
Typecode
Is Modifiertrue (Reason: This is labeled as "Is Modifier" because applications should not use a retired {{title}} without due consideration)
Summarytrue
Comments

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

Questionnaire.experimental
Element IdQuestionnaire.experimental
Definition

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

Control0..1
Typeboolean
Requirements

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

Summarytrue
Comments

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

Questionnaire.subjectType
Element IdQuestionnaire.subjectType
Definition

The types of subjects that can be the subject of responses created for the questionnaire.

Control0..*
Terminology BindingAny defined Resource Type name
Typecode
Summarytrue
Comments

If none are specified, then the subject is unlimited.

Questionnaire.date
Element IdQuestionnaire.date
Definition

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

Control0..1
TypedateTime
Alternate NamesRevision Date
Summarytrue
Comments

Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the questionnaire. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.

Questionnaire.publisher
Element IdQuestionnaire.publisher
Definition

The name of the organization or individual that published the questionnaire.

Control0..1
Typestring
Requirements

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

Summarytrue
Comments

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

Questionnaire.contact
Element IdQuestionnaire.contact
Definition

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

Control0..*
TypeContactDetail
Summarytrue
Comments

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

Questionnaire.description
Element IdQuestionnaire.description
Definition

A free text natural language description of the questionnaire from a consumer's perspective.

Control0..1
Typemarkdown
Comments

This description can be used to capture details such as why the questionnaire was built, comments about misuse, instructions for clinical use and interpretation, literature references, examples from the paper world, etc. It is not a rendering of the questionnaire as conveyed in the 'text' field of the resource itself. This item SHOULD be populated unless the information is available from context (e.g. the language of the questionnaire is presumed to be the predominant language in the place the questionnaire was created).

Questionnaire.useContext
Element IdQuestionnaire.useContext
Definition

The content was developed with a focus and intent of supporting the contexts that are listed. These terms may be used to assist with indexing and searching for appropriate questionnaire instances.

Control0..*
TypeUsageContext
Requirements

Assist in searching for appropriate content.

Summarytrue
Comments

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

Questionnaire.jurisdiction
Element IdQuestionnaire.jurisdiction
Definition

A legal or geographic region in which the questionnaire is intended to be used.

Control0..*
Terminology BindingJurisdiction (Extensible)
TypeCodeableConcept
Summarytrue
Comments

It may be possible for the questionnaire to be used in jurisdictions other than those for which it was originally designed or intended.

Questionnaire.purpose
Element IdQuestionnaire.purpose
Definition

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

Control0..1
Typemarkdown
Comments

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

Questionnaire.copyright
Element IdQuestionnaire.copyright
Definition

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

Control0..1
Typemarkdown
Requirements

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

Alternate NamesLicense; Restrictions
Questionnaire.approvalDate
Element IdQuestionnaire.approvalDate
Definition

The date on which the resource content was approved by the publisher. Approval happens once when the content is officially approved for usage.

Control0..1
Typedate
Comments

The 'date' element may be more recent than the approval date because of minor changes or editorial corrections.

Questionnaire.lastReviewDate
Element IdQuestionnaire.lastReviewDate
Definition

The date on which the resource content was last reviewed. Review happens periodically after approval but does not change the original approval date.

Control0..1
Typedate
Requirements

Gives a sense of how "current" the content is. Resources that have not been reviewed in a long time may have a risk of being less appropriate/relevant.

Comments

If specified, this date follows the original approval date.

Questionnaire.effectivePeriod
Element IdQuestionnaire.effectivePeriod
Definition

The period during which the questionnaire content was or is planned to be in active use.

Control0..1
TypePeriod
Requirements

Allows establishing a transition before a resource comes into effect and also allows for a sunsetting process when new versions of a the questionnaire are or are expected to be used instead.

Summarytrue
Comments

The effective period for a questionnaire determines when the content is applicable for usage and is independent of publication and review dates. For example, a measure intended to be used for the year 2016 might be published in 2015.

Questionnaire.code
Element IdQuestionnaire.code
Definition

An identifier for this question or group of questions in a particular terminology such as LOINC.

Control0..*
Terminology BindingQuestionnaire Question Codes (Example)
TypeCoding
Requirements

Allows linking of the complete Questionnaire resources to formal terminologies. It's common for "panels" of questions to be identified by a code.

Summarytrue
Questionnaire.item
Element IdQuestionnaire.item
Definition

A particular question, question grouping or display text that is part of the questionnaire.

Control0..*
Comments

The content of the questionnaire is constructed from an ordered, hierarchical collection of items.

Invariants
Defined on this element
que-1Rule Group items must have nested items, display items cannot have nested items(type='group' implies item.empty().not()) and (type.trace('type')='display' implies item.trace('item').empty())
que-3Rule Display items cannot have a "code" assertedtype!='display' or code.empty()
que-4Rule A question cannot have both answerOption and answerValueSetanswerOption.empty() or answerValueSet.empty()
que-5Rule Only 'choice' items can have answerValueSet(type ='choice' or type = 'open-choice' or type = 'decimal' or type = 'integer' or type = 'date' or type = 'dateTime' or type = 'time' or type = 'string' or type = 'quantity') or (answerValueSet.empty() and answerOption.empty())
que-6Rule Required and repeat aren't permitted for display itemstype!='display' or (required.empty() and repeats.empty())
que-8Rule Initial values can't be specified for groups or display items(type!='group' and type!='display') or initial.empty()
que-9Rule Read-only can't be specified for "display" itemstype!='display' or readOnly.empty()
que-10Rule Maximum length can only be declared for simple question types(type in ('boolean' | 'decimal' | 'integer' | 'string' | 'text' | 'url' | 'open-choice')) or maxLength.empty()
que-11Rule If one or more answerOption is present, initial[x] must be missinganswerOption.empty() or initial.empty()
que-12Rule If there are more than one enableWhen, enableBehavior must be specifiedenableWhen.count() > 2 implies enableBehavior.exists()
que-13Rule Can only have multiple initial values for repeating itemsrepeats=true or initial.count() <= 1
Affect this element
Questionnaire.item.linkId
Element IdQuestionnaire.item.linkId
Definition

An identifier that is unique within the Questionnaire allowing linkage to the equivalent item in a QuestionnaireResponse resource.

Control1..1
Typestring
Requirements

QuestionnaireResponse does not require omitted items to be included and may have some items that repeat, so linkage based on position alone is not sufficient.

Comments

This ''can'' be a meaningful identifier (e.g. a LOINC code) but is not intended to have any meaning. GUIDs or sequential numbers are appropriate here.

Questionnaire.item.definition
Element IdQuestionnaire.item.definition
Definition

This element is a URI that refers to an ElementDefinition that provides information about this item, including information that might otherwise be included in the instance of the Questionnaire resource. A detailed description of the construction of the URI is shown in Comments, below. If this element is present then the following element values MAY be derived from the Element Definition if the corresponding elements of this Questionnaire resource instance have no value:

  • code (ElementDefinition.code)
  • type (ElementDefinition.type)
  • required (ElementDefinition.min)
  • repeats (ElementDefinition.max)
  • maxLength (ElementDefinition.maxLength)
  • answerValueSet (ElementDefinition.binding)
  • options (ElementDefinition.binding).
Control0..1
Typeuri
Requirements

A common pattern is to define a set of data elements and then build multiple questionnaires for different circumstances to gather the data. This element provides traceability to the common definition and allows the content for the question to come from the underlying definition.

Comments

The uri refers to an ElementDefinition in a StructureDefinition and always starts with the canonical URL for the target resource. When referring to a StructureDefinition, a fragment identifier is used to specify the element definition by its id Element.id. E.g. http://hl7.org/fhir/StructureDefinition/Observation#Observation.value[x]. In the absence of a fragment identifier, the first/root element definition in the target is the matching element definition.

Questionnaire.item.code
Element IdQuestionnaire.item.code
Definition

A terminology code that corresponds to this group or question (e.g. a code from LOINC, which defines many questions and answers).

Control0..*
Terminology BindingQuestionnaire Question Codes (Example)
TypeCoding
Requirements

Allows linking of groups of questions to formal terminologies.

Comments

The value may come from the ElementDefinition referred to by .definition.

Invariants
Affect this element
que-3Rule Display items cannot have a "code" assertedtype!='display' or code.empty()
Questionnaire.item.prefix
Element IdQuestionnaire.item.prefix
Definition

A short label for a particular group, question or set of display text within the questionnaire used for reference by the individual completing the questionnaire.

Control0..1
Typestring
Requirements

Separating the label from the question text allows improved rendering. Also, instructions will often refer to specific prefixes, so there's a need for the questionnaire design to have control over what labels are used.

Alternate Nameslabel
Comments

These are generally unique within a questionnaire, though this is not guaranteed. Some questionnaires may have multiple questions with the same label with logic to control which gets exposed. Typically, these won't be used for "display" items, though such use is not prohibited. Systems SHOULD NOT generate their own prefixes if prefixes are defined for any items within a Questionnaire.

Questionnaire.item.text
Element IdQuestionnaire.item.text
Definition

The name of a section, the text of a question or text content for a display item.

Control0..1
Typestring
Questionnaire.item.type
Element IdQuestionnaire.item.type
Definition

The type of questionnaire item this is - whether text for display, a grouping of other items or a particular type of data to be captured (string, integer, coded choice, etc.).

Control1..1
Terminology BindingQuestionnaireItemType (Required)
Typecode
Requirements

Defines the format in which the user is to be prompted for the answer.

Comments

Additional constraints on the type of answer can be conveyed by extensions. The value may come from the ElementDefinition referred to by .definition.

Questionnaire.item.enableWhen
Element IdQuestionnaire.item.enableWhen
Definition

A constraint indicating that this item should only be enabled (displayed/allow answers to be captured) when the specified condition is true.

Control0..*
Is Modifiertrue (Reason: If enableWhen is present and the condition evaluates to false, then the Questionnaire behaves as though the elements weren't actually present)
Requirements

Allows questionnaires to adapt based on answers to other questions. E.g. If physical gender is specified as a male, no need to capture pregnancy history. Also allows conditional display of instructions or groups of questions.

Comments

If multiple repetitions of this extension are present, the item should be enabled when the condition for any of the repetitions is true. I.e. treat "enableWhen"s as being joined by an "or" clause. This element is a modifier because if enableWhen is present for an item, "required" is ignored unless one of the enableWhen conditions is met. When an item is disabled, all of its descendants are disabled, regardless of what their own enableWhen logic might evaluate to.

Invariants
Defined on this element
que-7Rule If the operator is 'exists', the value must be a booleanoperator = 'exists' implies (answer is Boolean)
Questionnaire.item.enableWhen.question
Element IdQuestionnaire.item.enableWhen.question
Definition

The linkId for the question whose answer (or lack of answer) governs whether this item is enabled.

Control1..1
Typestring
Comments

If multiple question occurrences are present for the same question (same linkId), then this refers to the nearest question occurrence reachable by tracing first the "ancestor" axis and then the "preceding" axis and then the "following" axis.

Questionnaire.item.enableWhen.operator
Element IdQuestionnaire.item.enableWhen.operator
Definition

Specifies the criteria by which the question is enabled.

Control1..1
Terminology BindingQuestionnaireItemOperator (Required)
Typecode
Questionnaire.item.enableWhen.answer[x]
Element IdQuestionnaire.item.enableWhen.answer[x]
Definition

A value that the referenced question is tested using the specified operator in order for the item to be enabled.

Control1..1
Terminology BindingQuestionnaire Answer Codes (Example)
Typeboolean|decimal|integer|date|dateTime|time|string|Coding|Quantity|Reference(Any)
[x] NoteSee Choice of Data Types for further information about how to use [x]
Invariants
Affect this element
que-7Rule If the operator is 'exists', the value must be a booleanoperator = 'exists' implies (answer is Boolean)
Questionnaire.item.enableBehavior
Element IdQuestionnaire.item.enableBehavior
Definition

Controls how multiple enableWhen values are interpreted - whether all or any must be true.

Control0..1
Terminology BindingEnableWhenBehavior (Required)
Typecode
Comments

This element must be specified if more than one enableWhen value is provided.

Invariants
Affect this element
que-12Rule If there are more than one enableWhen, enableBehavior must be specifiedenableWhen.count() > 2 implies enableBehavior.exists()
Questionnaire.item.required
Element IdQuestionnaire.item.required
Definition

An indication, if true, that the item must be present in a "completed" QuestionnaireResponse. If false, the item may be skipped when answering the questionnaire.

Control0..1
Typeboolean
Meaning if MissingItems are generally assumed not to be required unless explicitly specified. Systems SHOULD always populate this value
Comments

Questionnaire.item.required only has meaning for elements that are conditionally enabled with enableWhen if the condition evaluates to true. If an item that contains other items is marked as required, that does not automatically make the contained elements required (though required groups must contain at least one child element). The value may come from the ElementDefinition referred to by .definition.

Invariants
Affect this element
que-6Rule Required and repeat aren't permitted for display itemstype!='display' or (required.empty() and repeats.empty())
Questionnaire.item.repeats
Element IdQuestionnaire.item.repeats
Definition

An indication, if true, that the item may occur multiple times in the response, collecting multiple answers for questions or multiple sets of answers for groups.

Control0..1
Typeboolean
Meaning if MissingItems are generally assumed not to repeat unless explicitly specified. Systems SHOULD always populate this value
Requirements

Items may be used to create set of (related) questions that can be repeated to give multiple answers to such a set.

Comments

If a question is marked as repeats=true, then multiple answers can be provided for the question in the corresponding QuestionnaireResponse. When rendering the questionnaire, it is up to the rendering software whether to render the question text for each answer repetition (i.e. "repeat the question") or to simply allow entry/selection of multiple answers for the question (repeat the answers). Which is most appropriate visually may depend on the type of answer as well as whether there are nested items.

The resulting QuestionnaireResponse will be populated the same way regardless of rendering - one 'question' item with multiple answer values.

The value may come from the ElementDefinition referred to by .definition.

Invariants
Affect this element
que-6Rule Required and repeat aren't permitted for display itemstype!='display' or (required.empty() and repeats.empty())
Questionnaire.item.readOnly
Element IdQuestionnaire.item.readOnly
Definition

An indication, when true, that the value cannot be changed by a human respondent to the Questionnaire.

Control0..1
Typeboolean
Requirements

Allows certain information to be phrased (and rendered) as a question and an answer, while keeping users from changing it. May also be useful for preventing changes to pre-populated portions of a questionnaire, for calculated values, etc.

Comments

The value of readOnly elements can be established by asserting extensions for defaultValues, linkages that support pre-population and/or extensions that support calculation based on other answers.

Invariants
Affect this element
que-9Rule Read-only can't be specified for "display" itemstype!='display' or readOnly.empty()
Questionnaire.item.maxLength
Element IdQuestionnaire.item.maxLength
Definition

The maximum number of characters that are permitted in the answer to be considered a "valid" QuestionnaireResponse.

Control0..1
Typeinteger
Comments

For base64binary, reflects the number of characters representing the encoded data, not the number of bytes of the binary data. The value may come from the ElementDefinition referred to by .definition.

Invariants
Affect this element
que-10Rule Maximum length can only be declared for simple question types(type in ('boolean' | 'decimal' | 'integer' | 'string' | 'text' | 'url' | 'open-choice')) or maxLength.empty()
Questionnaire.item.answerValueSet
Element IdQuestionnaire.item.answerValueSet
Definition

A reference to a value set containing a list of codes representing permitted answers for a "choice" or "open-choice" question.

Control0..1
Typecanonical(ValueSet)
Comments

LOINC defines many useful value sets for questionnaire responses. See LOINC Answer Lists. The value may come from the ElementDefinition referred to by .definition.

Invariants
Affect this element
que-4Rule A question cannot have both answerOption and answerValueSetanswerOption.empty() or answerValueSet.empty()
que-5Rule Only 'choice' items can have answerValueSet(type ='choice' or type = 'open-choice' or type = 'decimal' or type = 'integer' or type = 'date' or type = 'dateTime' or type = 'time' or type = 'string' or type = 'quantity') or (answerValueSet.empty() and answerOption.empty())
Questionnaire.item.answerOption
Element IdQuestionnaire.item.answerOption
Definition

One of the permitted answers for a "choice" or "open-choice" question.

Control0..*
Comments

This element can be used when the value set machinery of answerValueSet is deemed too cumbersome or when there's a need to capture possible answers that are not codes.

Invariants
Affect this element
que-4Rule A question cannot have both answerOption and answerValueSetanswerOption.empty() or answerValueSet.empty()
que-5Rule Only 'choice' items can have answerValueSet(type ='choice' or type = 'open-choice' or type = 'decimal' or type = 'integer' or type = 'date' or type = 'dateTime' or type = 'time' or type = 'string' or type = 'quantity') or (answerValueSet.empty() and answerOption.empty())
Questionnaire.item.answerOption.value[x]
Element IdQuestionnaire.item.answerOption.value[x]
Definition

A potential answer that's allowed as the answer to this question.

Control1..1
Terminology BindingQuestionnaire Answer Codes (Example)
Typeinteger|date|time|string|Coding|Reference(Any)
[x] NoteSee Choice of Data Types for further information about how to use [x]
Comments

The data type of the value must agree with the item.type.

Questionnaire.item.answerOption.initialSelected
Element IdQuestionnaire.item.answerOption.initialSelected
Definition

Indicates whether the answer value is selected when the list of possible answers is initially shown.

Control0..1
Typeboolean
Meaning if MissingOnly selected items explicitly marked to be selected
Comments

Use this instead of initial[v] if answerValueSet is present.

Questionnaire.item.initial
Element IdQuestionnaire.item.initial
Definition

One or more values that should be pre-populated in the answer when initially rendering the questionnaire for user input.

Control0..*
Requirements

In some workflows, having defaults saves time.

Comments

The user is allowed to change the value and override the default (unless marked as read-only). If the user doesn't change the value, then this initial value will be persisted when the QuestionnaireResponse is initially created. Note that initial values can influence results. The data type of initial[x] must agree with the item.type, and only repeating items can have more then one initial value.

Invariants
Affect this element
que-8Rule Initial values can't be specified for groups or display items(type!='group' and type!='display') or initial.empty()
que-13Rule Can only have multiple initial values for repeating itemsrepeats=true or initial.count() <= 1
Questionnaire.item.initial.value[x]
Element IdQuestionnaire.item.initial.value[x]
Definition

The actual value to for an initial answer.

Control1..1
Terminology BindingQuestionnaire Answer Codes (Example)
Typeboolean|decimal|integer|date|dateTime|time|string|uri|Attachment|Coding|Quantity|Reference(Any)
[x] NoteSee Choice of Data Types for further information about how to use [x]
Comments

The type of the initial value must be consistent with the type of the item.

Questionnaire.item.item
Element IdQuestionnaire.item.item
Definition

Text, questions and other groups to be nested beneath a question or group.

Control0..*
TypeSee Questionnaire.item
Requirements

Reports can consist of complex nested groups.

Comments

There is no specified limit to the depth of nesting. However, Questionnaire authors are encouraged to consider the impact on the user and user interface of overly deep nesting.

Invariants
Affect this element
que-1Rule Group items must have nested items, display items cannot have nested items(type='group' implies item.empty().not()) and (type.trace('type')='display' implies item.trace('item').empty())