| Source Element | Usage | Target |
| ResearchElementDefinition | UseExtension | http://hl7.org/fhir/4.3/StructureDefinition/extension-ResearchElementDefinition |
| ResearchElementDefinition.id | UseExtensionFromAncestor | - |
| ResearchElementDefinition.meta | UseExtensionFromAncestor | - |
| ResearchElementDefinition.implicitRules | UseExtensionFromAncestor | - |
| ResearchElementDefinition.language | UseExtensionFromAncestor | - |
| ResearchElementDefinition.text | UseExtensionFromAncestor | - |
| ResearchElementDefinition.contained | UseExtensionFromAncestor | - |
| ResearchElementDefinition.extension | UseExtensionFromAncestor | - |
| ResearchElementDefinition.modifierExtension | UseExtensionFromAncestor | - |
| ResearchElementDefinition.url | UseExtensionFromAncestor | - |
| ResearchElementDefinition.identifier | UseExtensionFromAncestor | - |
| ResearchElementDefinition.version | UseExtensionFromAncestor | - |
| ResearchElementDefinition.name | UseExtensionFromAncestor | - |
| ResearchElementDefinition.title | UseExtensionFromAncestor | - |
| ResearchElementDefinition.shortTitle | UseExtensionFromAncestor | - |
| ResearchElementDefinition.subtitle | UseExtensionFromAncestor | - |
| ResearchElementDefinition.status | UseExtensionFromAncestor | - |
| ResearchElementDefinition.experimental | UseExtensionFromAncestor | - |
| ResearchElementDefinition.subject[x] | UseExtensionFromAncestor | - |
| ResearchElementDefinition.date | UseExtensionFromAncestor | - |
| ResearchElementDefinition.publisher | UseExtensionFromAncestor | - |
| ResearchElementDefinition.contact | UseExtensionFromAncestor | - |
| ResearchElementDefinition.description | UseExtensionFromAncestor | - |
| ResearchElementDefinition.comment | UseExtensionFromAncestor | - |
| ResearchElementDefinition.useContext | UseExtensionFromAncestor | - |
| ResearchElementDefinition.jurisdiction | UseExtensionFromAncestor | - |
| ResearchElementDefinition.purpose | UseExtensionFromAncestor | - |
| ResearchElementDefinition.usage | UseExtensionFromAncestor | - |
| ResearchElementDefinition.copyright | UseExtensionFromAncestor | - |
| ResearchElementDefinition.approvalDate | UseExtensionFromAncestor | - |
| ResearchElementDefinition.lastReviewDate | UseExtensionFromAncestor | - |
| ResearchElementDefinition.effectivePeriod | UseExtensionFromAncestor | - |
| ResearchElementDefinition.topic | UseExtensionFromAncestor | - |
| ResearchElementDefinition.author | UseExtensionFromAncestor | - |
| ResearchElementDefinition.editor | UseExtensionFromAncestor | - |
| ResearchElementDefinition.reviewer | UseExtensionFromAncestor | - |
| ResearchElementDefinition.endorser | UseExtensionFromAncestor | - |
| ResearchElementDefinition.relatedArtifact | UseExtensionFromAncestor | - |
| ResearchElementDefinition.library | UseExtensionFromAncestor | - |
| ResearchElementDefinition.type | UseExtensionFromAncestor | - |
| ResearchElementDefinition.variableType | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.id | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.extension | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.modifierExtension | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.definition[x] | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.usageContext | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.exclude | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.unitOfMeasure | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.studyEffectiveDescription | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.studyEffective[x] | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.studyEffectiveTimeFromStart | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.studyEffectiveGroupMeasure | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.participantEffectiveDescription | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.participantEffective[x] | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.participantEffectiveTimeFromStart | UseExtensionFromAncestor | - |
| ResearchElementDefinition.characteristic.participantEffectiveGroupMeasure | UseExtensionFromAncestor | - |