# text.div
Name | Flags | Card. | Type | Description & Constraints
QuestionnaireResponse | | 0..* | QuestionnaireResponse | A structured set of questions and their answers
meta | | | |
profile | S | 1..1 | canonical(StructureDefinition) | Profiles this resource claims to conform to

Slices for extension

1..*

Extension

Extension
Slice: Unordered, Open by value:url

lastChangedBy

1..1

Reference(Practitioner)

Last changed by
URL: https://fhir.mona.icu/StructureDefinition/lastChangedBy

questionnaire | | 1..1 | canonical(Questionnaire) | Form being answered
subject | | 1..1 | Reference(Patient) | The subject of the questions
encounter | | 1..1 | Reference(Encounter) | Encounter created as part of
authored | | 1..1 | dateTime | Date the answers were gathered
author | | 1..1 | Reference(Practitioner) | Person who received and recorded the answers
source | | 1..1 | Reference(Practitioner) | The person who answered the questions
item | | 1..* | BackboneElement | Groups and questions

Documentation for this format

# title
Mona Entry Control Questionnaire Response

# description
The definition of a Questionnaire-Response of a Entry-Control-Questionnaire.

# snapshot.element[].short
A structured set of questions and their answers

# snapshot.element[].definition
A structured set of questions and their answers. The questions are ordered and grouped into coherent subsets, corresponding to the structure of the grouping of the questionnaire being responded to.

# snapshot.element[].comment
The QuestionnaireResponse contains enough information about the questions asked and their organization that it can be interpreted somewhat independently from the Questionnaire it is based on.  I.e. You don't need access to the Questionnaire in order to extract basic information from a QuestionnaireResponse.

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL NOT contain nested Resources

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource

# snapshot.element[].constraint[].human
If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated

# snapshot.element[].constraint[].human
If a resource is contained in another resource, it SHALL NOT have a security label

# snapshot.element[].constraint[].extension[].valueMarkdown
When a resource has no narrative, only systems that fully understand the data can display the resource to a human safely. Including a human readable representation in the resource makes for a much more robust eco-system and cheaper handling of resources by intermediary systems. Some ecosystems restrict distribution of resources to only those systems that do fully understand the resources, and as a consequence implementers may believe that the narrative is superfluous. However experience shows that such eco-systems often open up to new participants over time.

# snapshot.element[].constraint[].human
A resource should have narrative for robust management

# snapshot.element[].definition
The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

# snapshot.element[].comment
The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

# snapshot.element[].definition
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

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

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional content defined by implementations

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
When the resource last changed - e.g. when the version changed.

# snapshot.element[].comment
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](http://hl7.org/fhir/R4/http.html#read) interaction.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Identifies where the resource comes from

# snapshot.element[].definition
A uri that identifies the source system of the resource. This provides a minimal amount of [Provenance](http://hl7.org/fhir/R4/provenance.html#) 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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Profiles this resource claims to conform to

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Security Labels applied to this resource

# snapshot.element[].definition
Security labels applied to this resource. These tags connect specific resources to the overall security policy and infrastructure.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Security Labels from the Healthcare Privacy and Security Classification System.

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Codes that represent various types of tags, commonly workflow-related; e.g. "Needs review by Dr. Jones".

# snapshot.element[].short
A set of rules under which this content was created

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].isModifierReason
This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation

# snapshot.element[].definition
The base language in which the resource is written.

# snapshot.element[].comment
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).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Text summary of the resource, for human interpretation

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
Stores which practitioner last changed the resource.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
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).

# snapshot.element[].comment
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.

# snapshot.element[].requirements
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](http://hl7.org/fhir/R4/extensibility.html#modifierExtension).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].isModifierReason
Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them

# snapshot.element[].definition
A business identifier assigned to a particular completed (or partially completed) questionnaire.

# snapshot.element[].requirements
Used for tracking, registration and other business purposes.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Request fulfilled by this QuestionnaireResponse

# snapshot.element[].definition
The order, proposal or plan that is fulfilled in whole or in part by this QuestionnaireResponse.  For example, a ServiceRequest seeking an intake assessment or a decision support recommendation to assess for post-partum depression.

# snapshot.element[].requirements
Supports traceability of responsibility for the action and allows linkage of an action to the recommendations acted upon.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
A procedure or observation that this questionnaire was performed as part of the execution of.  For example, the surgery a checklist was executed as part of.

# snapshot.element[].comment
Composition of questionnaire responses will be handled by the parent questionnaire having answers that reference the child questionnaire.  For relationships to referrals, and other types of requests, use basedOn.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The Questionnaire that defines and organizes the questions for which answers are being provided.

# snapshot.element[].comment
If a QuestionnaireResponse references a Questionnaire, then the QuestionnaireResponse structure must be consistent with the Questionnaire (i.e. questions must be organized into the same groups, nested questions must still be nested, etc.).

# snapshot.element[].requirements
Needed to allow editing of the questionnaire response in a manner that enforces the constraints of the original form.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
in-progress | completed | amended | entered-in-error | stopped

# snapshot.element[].definition
The position of the questionnaire response within its overall lifecycle.

# snapshot.element[].comment
This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

# snapshot.element[].requirements
The information on Questionnaire resources  may possibly be gathered during multiple sessions and altered after considered being finished.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].isModifierReason
This element is labelled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid

# snapshot.element[].binding.description
Lifecycle status of the questionnaire response.

# snapshot.element[].mapping[].map
.statusCode (also whether there's a revisionControlAct - and possibly mood to distinguish "in-progress" from "published)

# snapshot.element[].definition
The subject of the questionnaire response.  This could be a patient, organization, practitioner, device, etc.  This is who/what the answers apply to, but is not necessarily the source of information.

# snapshot.element[].comment
If the Questionnaire declared a subjectType, the resource pointed to by this element must be an instance of one of the listed types.

# snapshot.element[].requirements
Allows linking the answers to the individual the answers describe.  May also affect access control.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The Encounter during which this questionnaire response was created or to which the creation of this record is tightly associated.

# snapshot.element[].comment
This will typically be the encounter the event occurred within, but some activities may be initiated prior to or after the official completion of an encounter but still be tied to the context of the encounter. A questionnaire that was initiated during an encounter but not fully completed during the encounter would still generally be associated with the encounter.

# snapshot.element[].requirements
Provides context for the information that was captured.  May also affect access control.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The date and/or time that this set of answers were last changed.

# snapshot.element[].comment
May be different from the lastUpdateTime of the resource itself, because that reflects when the data was known to the server, not when the data was captured.

This element is optional to allow for systems that might not know the value, however it SHOULD be populated if possible.

# snapshot.element[].requirements
Clinicians need to be able to check the date that the information in the questionnaire was collected, to derive the context of the answers.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Person who received and recorded the answers

# snapshot.element[].definition
Person who received the answers to the questions in the QuestionnaireResponse and recorded them in the system.

# snapshot.element[].comment
Mapping a subject's answers to multiple choice options and determining what to put in the textual answer is a matter of interpretation.  Authoring by device would indicate that some portion of the questionnaire had been auto-populated.

# snapshot.element[].requirements
Need to know who interpreted the subject's answers to the questions in the questionnaire, and selected the appropriate options for answers.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The person who answered the questions about the subject.

# snapshot.element[].comment
If not specified, no inference can be made about who provided the data.

# snapshot.element[].requirements
When answering questions about a subject that is minor, incapable of answering or an animal, another human source may answer the questions.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
A group or question item from the original questionnaire for which answers are provided.

# snapshot.element[].comment
Groups cannot have answers and therefore must nest directly within item. When dealing with questions, nesting must occur within each answer because some questions may have multiple answers (and the nesting occurs for each answer).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Nested item can't be beneath both item and answer

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

# snapshot.element[].short
Additional content defined by implementations

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Extensions that cannot be ignored even if unrecognized

# snapshot.element[].definition
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).

# snapshot.element[].comment
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.

# snapshot.element[].requirements
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](http://hl7.org/fhir/R4/extensibility.html#modifierExtension).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].isModifierReason
Modifier extensions are expected to modify the meaning or interpretation of the element that contains them

# snapshot.element[].short
Pointer to specific item from Questionnaire

# snapshot.element[].definition
The item from the Questionnaire that corresponds to this item in the QuestionnaireResponse resource.

# snapshot.element[].requirements
Items can repeat in the answers, so a direct 1..1 correspondence by position might not exist - requiring correspondence by identifier.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
ElementDefinition - details for the item

# snapshot.element[].definition
A reference to an [ElementDefinition](http://hl7.org/fhir/R4/elementdefinition.html) that provides the details for the item.

# snapshot.element[].comment
The ElementDefinition must be in a [StructureDefinition](http://hl7.org/fhir/R4/structuredefinition.html#), and must have a fragment identifier that identifies the specific data element by its id (Element.id). E.g. http://hl7.org/fhir/StructureDefinition/Observation#Observation.value[x].

There is no need for this element if the item pointed to by the linkId has a definition listed.

# snapshot.element[].requirements
A common pattern is to define a set of data elements, and then build multiple different questionnaires for different circumstances to gather the data. This element provides traceability to the common definition.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
Text that is displayed above the contents of the group or as the text of the question being answered.

# snapshot.element[].requirements
Allows the questionnaire response to be read without access to the questionnaire.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The respondent's answer(s) to the question.

# snapshot.element[].comment
The value is nested because we cannot have a repeating structure that has variable type.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

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

# snapshot.element[].short
Additional content defined by implementations

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Extensions that cannot be ignored even if unrecognized

# snapshot.element[].definition
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).

# snapshot.element[].comment
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.

# snapshot.element[].requirements
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](http://hl7.org/fhir/R4/extensibility.html#modifierExtension).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].isModifierReason
Modifier extensions are expected to modify the meaning or interpretation of the element that contains them

# snapshot.element[].definition
The answer (or one of the answers) provided by the respondent to the question.

# snapshot.element[].comment
More complex structures (Attachment, Resource and Quantity) will typically be limited to electronic forms that can expose an appropriate user interface to capture the components and enforce the constraints of a complex data type.  Additional complex types can be introduced through extensions. Must match the datatype specified by Questionnaire.item.type in the corresponding Questionnaire.

# snapshot.element[].requirements
Ability to retain a single-valued answer to a question.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Code indicating the response provided for a question.

# snapshot.element[].definition
Nested groups and/or questions found within this particular answer.

# snapshot.element[].requirements
It is useful to have "sub-questions", questions which normally appear when certain answers are given and which collect additional details.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
Questions or sub-groups nested beneath a question or group.

# snapshot.element[].requirements
Reports can consist of complex nested groups.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())