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

Additional details on the use of this extension can be found on the [Form Behavior](/sdc-behavior#enableWhenExpression) page. For information on how `enableWhenExpression` enables complex conditional logic, refer to the [Expressions page - enableWhenExpression](/sdc-expressions#enableWhenExpression) section.