Structured Data Capture
4.0.0 - International flag

Structured Data Capture, published by HL7 International / FHIR Infrastructure. This guide is not an authorized publication; it is the continuous build for version 4.0.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/sdc/ and changes regularly. See the Directory of published versions

Extension: Answer Expression

Official URL: http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-answerExpression Version: 4.0.0
Standards status: Trial-use Active as of 2025-10-22 Maturity Level: 4 Computable Name: AnswerExpressionExtension
Other Identifiers: OID:2.16.840.1.113883.4.642.40.17.42.11

An expression (FHIRPath, CQL or FHIR Query) that resolves to a list of permitted answers for the question item or that establishes context for a group item. The user may select from among the list to choose answers for the question.

Context of Use

Additional details on the use of this extension can be found on the Form Behavior and Questionnaire Population pages. For details on how answerExpression is used to generate allowed answer options, refer to the Expressions page - answerExpression section.

Usage info

Usages:

You can also check for usages in the FHIR IG Statistics

Formal Views of Extension Content

Description Differentials, Snapshots, and other representations.

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..1 Extension Expression for possible answers
... extension 0..0
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-answerExpression"
... value[x] 0..1 Expression Value of extension

doco Documentation for this format
NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..1 Extension Expression for possible answers
... id 0..1 string Unique id for inter-element referencing
... extension 0..0
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-answerExpression"

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
ele-1 error **ALL** elements All FHIR elements must have a @value or children hasValue() or (children().count() > id.count())
ext-1 error **ALL** extensions Must have either extensions or value[x], not both extension.exists() != value.exists()

Summary

Simple Extension with the type Expression: An expression (FHIRPath, CQL or FHIR Query) that resolves to a list of permitted answers for the question item or that establishes context for a group item. The user may select from among the list to choose answers for the question.

Maturity: 4

Differential ViewDifferential View

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..1 Extension Expression for possible answers
... extension 0..0
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-answerExpression"
... value[x] 0..1 Expression Value of extension

doco Documentation for this format

Snapshot View

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..1 Extension Expression for possible answers
... id 0..1 string Unique id for inter-element referencing
... extension 0..0
... url 1..1 uri "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-answerExpression"

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
ele-1 error **ALL** elements All FHIR elements must have a @value or children hasValue() or (children().count() > id.count())
ext-1 error **ALL** extensions Must have either extensions or value[x], not both extension.exists() != value.exists()

Summary

Simple Extension with the type Expression: An expression (FHIRPath, CQL or FHIR Query) that resolves to a list of permitted answers for the question item or that establishes context for a group item. The user may select from among the list to choose answers for the question.

Maturity: 4

 

Other representations of profile: CSV, Excel, Schematron