If true, indicates that the Questionnaire relies on metadata from the ElementDefinitions referenced by item.definition and that rendering or validating the Questionnaire is likely to be unsafe if the system isn't capable of resolving the definition and using the metadata found there.

Allows disabling certain questionnaire options for the containing item based on evaluating expressions.

The minimum number of times the group must appear, or the minimum number of answers for a question - when greater than 1.

The maximum number of times the group must appear, or the maximum number of answers for a question - when greater than 1 and not unlimited.

If true, indicates that the extended item should not be displayed to the user.

The type of data entry control or structure that should be used to render the item. Certain item controls only make sense for certain types of items. For example, a radio button doesn't make sense for a question where repeats=true; few systems will know how to implement a 'slider' control if the question type is 'Attachment', etc. Form fillers are allowed to ignore item controls that don't make sense (or that they don't know how to handle) for the type of item the extension appears on. If the extension is ignored, the form filler will use whatever display control it supports that works best for the type of item present. Similarly, form authoring tools may raise validation issues or prohibit the selection of certain control types based on the characteristics of the item.

Identifies the desired orientation when rendering a list of choices (typically radio-box or check-box lists).

Where the type for a question is "Reference", indicates a type of resource that is permitted.

Where the type for a question is "Reference", indicates a profile that the resource instances pointed to in answers to this question must be valid against.

Identifies a filter to apply when looking up candidate answers for the question. This extension has been replaced by the Structured Data Capture candidateExpression extension.

Describes the intended purpose of the rendered text. For example - instructions, guidance on access control, maintenance information, etc.

For questionnaires generated from FHIR profiles, indicates the FHIR data type or resource type that corresponds to this node.

Provides a computable unit of measure associated with numeric questions to support subsequent computation on responses. This is for use on items of type integer and decimal, and its purpose is to support converting the integer or decimal answer into a Quantity when extracting the data into a resource. If a 'display' value is provided for valueCoding of this extension and the associated question item does not have a child 'display' item with an itemControl extension of 'unit', then form fillers SHOULD take the display value of this extension and use it as as the unit display.

A unit that the user may choose when providing a quantity value.

A set of units that the user may choose when providing a quantity value.

The label to list in front of a code when presenting a list of possible values in a questionnaire-like fashion.

If true, indicates that if this answerOption is selected, no other possible answers may be selected, even if the item is a repeating question.

Identifies that the specified element should only appear in certain "modes" of operation.

A URL that resolves to additional supporting information or guidance related to the question.

This identifies the underlying type in a profile, when a questionnaire is generated from a profile.

Indicates that a signature (of the specified type) is needed when completing the QuestionnaireResponse.

An invariant that must be satisfied before responses to the questionnaire can be considered "complete".

For slider-based controls, indicates the step size to use when toggling the control up or down.