---
type: "sdc-page"
title: "SDC: StructureDefinition-sdc-questionnaire-extractAllocateId-intro"
source: "sdc/input/pagecontent/StructureDefinition-sdc-questionnaire-extractAllocateId-intro.md"
---
# SDC: StructureDefinition-sdc-questionnaire-extractAllocateId-intro

<a name="scope"></a>
## Scope and Usage
This extension currently only applies to either the [definition](/sdc-extraction#definition-extract) or [template](/sdc-extraction#template-extract) extraction processing.

The `value` will be made available as a named variable in extract fhirpath expressions, and only within the scope of the item that contains the extension, and any child items of that collection.

When defined at the root of a questionnaire, the value will be available for all items in the questionnaire (and only allocated once).

When defined on a repeating item, the value will be new for each iteration of the item in the QuestionnaireResponse answers.