> ## Documentation Index
> Fetch the complete documentation index at: https://docs.metriport.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ResearchElementDefinition

> The ResearchElementDefinition resource describes a PICO element that knowledge (evidence, assertion, recommendation) is about.

## Properties

| Name | Required | Type | Description |
| - | - | - | - |
| url | No | uri | Canonical identifier for this research element definition, represented as a URI (globally unique) |
| identifier | No | [Identifier](/medical-api/fhir/data-types/identifier)\[] | Additional identifier for the research element definition |
| version | No | string | Business version of the research element definition |
| name | No | string | Name for this research element definition (computer friendly) |
| title | No | string | Name for this research element definition (human friendly) |
| shortTitle | No | string | Title for use in informal contexts |
| subtitle | No | string | Subordinate title of the ResearchElementDefinition |
| status | Yes | code | draft / active / retired / unknown |
| experimental | No | boolean | For testing purposes, not real usage |
| subject\[x] | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept), Reference\<[Group](/medical-api/fhir/resources/group)> | E.g. Patient, Practitioner, RelatedPerson, Organization, Location, Device |
| date | No | dateTime | Date last changed |
| publisher | No | string | Name of the publisher (organization or individual) |
| contact | No | [ContactDetail](/medical-api/fhir/data-types/contactdetail)\[] | Contact details for the publisher |
| description | No | markdown | Natural language description of the research element definition |
| comment | No | string\[] | Used for footnotes or explanatory notes |
| useContext | No | [UsageContext](/medical-api/fhir/data-types/usagecontext)\[] | The context that the content is intended to support |
| jurisdiction | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | Intended jurisdiction for research element definition (if applicable) |
| purpose | No | markdown | Why this research element definition is defined |
| usage | No | string | Describes the clinical usage of the ResearchElementDefinition |
| copyright | No | markdown | Use and/or publishing restrictions |
| approvalDate | No | date | When the research element definition was approved by publisher |
| lastReviewDate | No | date | When the research element definition was last reviewed |
| effectivePeriod | No | [Period](/medical-api/fhir/data-types/period) | When the research element definition is expected to be used |
| topic | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | The category of the ResearchElementDefinition, such as Education, Treatment, Assessment, etc. |
| author | No | [ContactDetail](/medical-api/fhir/data-types/contactdetail)\[] | Who authored the content |
| editor | No | [ContactDetail](/medical-api/fhir/data-types/contactdetail)\[] | Who edited the content |
| reviewer | No | [ContactDetail](/medical-api/fhir/data-types/contactdetail)\[] | Who reviewed the content |
| endorser | No | [ContactDetail](/medical-api/fhir/data-types/contactdetail)\[] | Who endorsed the content |
| relatedArtifact | No | [RelatedArtifact](/medical-api/fhir/data-types/relatedartifact)\[] | Additional documentation, citations, etc. |
| library | No | canonical\[] | Logic used by the ResearchElementDefinition |
| type | Yes | code | population / exposure / outcome |
| variableType | No | code | dichotomous / continuous / descriptive |
| characteristic | Yes | ResearchElementDefinitionCharacteristic | What defines the members of the research element |
| - id | No | string | Unique id for inter-element referencing |
| - extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations |
| - modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored even if unrecognized |
| - definition\[x] | Yes | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept), canonical, [Expression](/medical-api/fhir/data-types/expression), [DataRequirement](/medical-api/fhir/data-types/datarequirement) | What code or expression defines members? |
| - usageContext | No | [UsageContext](/medical-api/fhir/data-types/usagecontext)\[] | What code/value pairs define members? |
| - exclude | No | boolean | Whether the characteristic includes or excludes members |
| - unitOfMeasure | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | What unit is the outcome described in? |
| - studyEffectiveDescription | No | string | What time period does the study cover |
| - studyEffective\[x] | No | dateTime, [Period](/medical-api/fhir/data-types/period), [Duration](/medical-api/fhir/data-types/duration), [Timing](/medical-api/fhir/data-types/timing) | What time period does the study cover |
| - studyEffectiveTimeFromStart | No | [Duration](/medical-api/fhir/data-types/duration) | Observation time from study start |
| - studyEffectiveGroupMeasure | No | code | mean / median / mean-of-mean / mean-of-median / median-of-mean / median-of-median |
| - participantEffectiveDescription | No | string | What time period do participants cover |
| - participantEffective\[x] | No | dateTime, [Period](/medical-api/fhir/data-types/period), [Duration](/medical-api/fhir/data-types/duration), [Timing](/medical-api/fhir/data-types/timing) | What time period do participants cover |
| - participantEffectiveTimeFromStart | No | [Duration](/medical-api/fhir/data-types/duration) | Observation time from study start |
| - participantEffectiveGroupMeasure | No | code | mean / median / mean-of-mean / mean-of-median / median-of-mean / median-of-median |

## Search Parameters

| Name | Type | Description | Expression |
| - | - | - | - |
| composed-of | reference | What resource is being referenced | ResearchElementDefinition.relatedArtifact |
| context | token | A use context assigned to the research element definition | ResearchElementDefinition.useContext.value |
| context-quantity | quantity | A quantity- or range-valued use context assigned to the research element definition | ResearchElementDefinition.useContext.value |
| context-type | token | A type of use context assigned to the research element definition | ResearchElementDefinition.useContext.code |
| date | date | The research element definition publication date | ResearchElementDefinition.date |
| depends-on | reference | What resource is being referenced | ResearchElementDefinition.relatedArtifact |
| derived-from | reference | What resource is being referenced | ResearchElementDefinition.relatedArtifact |
| description | string | The description of the research element definition | ResearchElementDefinition.description |
| effective | date | The time during which the research element definition is intended to be in use | ResearchElementDefinition.effectivePeriod |
| identifier | token | External identifier for the research element definition | ResearchElementDefinition.identifier |
| jurisdiction | token | Intended jurisdiction for the research element definition | ResearchElementDefinition.jurisdiction |
| name | string | Computationally friendly name of the research element definition | ResearchElementDefinition.name |
| predecessor | reference | What resource is being referenced | ResearchElementDefinition.relatedArtifact |
| publisher | string | Name of the publisher of the research element definition | ResearchElementDefinition.publisher |
| status | token | The current status of the research element definition | ResearchElementDefinition.status |
| successor | reference | What resource is being referenced | ResearchElementDefinition.relatedArtifact |
| title | string | The human-friendly name of the research element definition | ResearchElementDefinition.title |
| topic | token | Topics associated with the ResearchElementDefinition | ResearchElementDefinition.topic |
| url | uri | The uri that identifies the research element definition | ResearchElementDefinition.url |
| version | token | The business version of the research element definition | ResearchElementDefinition.version |
| context-type-quantity | composite | A use context type and quantity- or range-based value assigned to the research element definition | ResearchElementDefinition.useContext |
| context-type-value | composite | A use context type and value assigned to the research element definition | ResearchElementDefinition.useContext |

## Inherited Properties

| Name | Required | Type | Description |
| - | - | - | - |
| id | No | string | Logical id of this artifact |
| meta | No | [Meta](/medical-api/fhir/data-types/meta) | Metadata about the resource |
| implicitRules | No | uri | A set of rules under which this content was created |
| language | No | code | Language of the resource content |
| text | No | [Narrative](/medical-api/fhir/data-types/narrative) | Text summary of the resource, for human interpretation |
| contained | No | Resource\[] | Contained, inline Resources |
| extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations |
| modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored |

To view the FHIR specification for this resource, see [ResearchElementDefinition](https://www.hl7.org/fhir/StructureDefinition/ResearchElementDefinition).