---
type: "codesystem"
title: "Evidence Variable Handling Example"
codesystem: "variable-handling-example"
---
# Evidence Variable Handling Example

- **Official URL**: http://hl7.org/fhir/variable-handling-example
- **Version**: 6.0.0
- **Status**: active
- **Name**: EvidenceVariableHandlingExample
- **Title**: Evidence Variable Handling Example
- **Publisher**: HL7 (FHIR Project)
- **Description**: The handling of the variable in statistical analysis for exposures or outcomes (E.g. Dichotomous, Continuous, Descriptive).
- **Case Sensitive**: true
- **Content**: complete

## Concepts

| Code | Display | Definition |
| --- | --- | --- |
| boolean | boolean variable | A boolean variable is a variable which is defined to have only 2 possible values: True or False. |
| continuous | continuous variable | A continuous variable is one for which, within the limits the variable ranges, any value is possible (from STATO http://purl.obolibrary.org/obo/STATO_0000251). |
| dichotomous | dichotomous variable | A dichotomous variable is a categorical variable which is defined to have only 2 categories or possible values (from STATO http://purl.obolibrary.org/obo/STATO_0000090). |
| ordinal | ordinal variable | An ordinal variable is a categorical variable where the discrete possible values are ordered or correspond to an implicit ranking (from STATO http://purl.obolibrary.org/obo/STATO_0000228). |
| polychotomous | polychotomous variable | A polychotomous variable is a categorical variable which is defined to have minimally 2 categories or possible values. (from STATO  http://purl.obolibrary.org/obo/STATO_0000087).  Suggestion to limit code use to situations when neither dichotomous nor ordinal variables apply. |
| time-to-event | time-to-event | time-to-event |
| not-specified | not-specified | not-specified |

## CodeSystem XML



```xml
<?xml version="1.0" encoding="UTF-8"?>

<CodeSystem xmlns="http://hl7.org/fhir">
  <id value="variable-handling-example"/>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-wg">
    <valueCode value="cds"/>
  </extension>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
    <valueCode value="normative"/>
  </extension>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
    <valueInteger value="5"/>
  </extension>
  <url value="http://hl7.org/fhir/variable-handling-example"/>
  <version value="6.0.0"/>
  <name value="EvidenceVariableHandlingExample"/>
  <title value="Evidence Variable Handling Example"/>
  <status value="active"/>
  <experimental value="false"/>
  <date value="2021-01-05T10:01:24+11:00"/>
  <publisher value="HL7 (FHIR Project)"/>
  <contact>
    <telecom>
      <system value="url"/>
      <value value="http://hl7.org/fhir"/>
    </telecom>
    <telecom>
      <system value="email"/>
      <value value="fhir@lists.hl7.org"/>
    </telecom>
  </contact>
  <description value="The handling of the variable in statistical analysis for exposures or outcomes (E.g. Dichotomous, Continuous, Descriptive)."/>
  <caseSensitive value="true"/>
  <valueSet value="http://hl7.org/fhir/ValueSet/variable-handling-example"/>
  <content value="complete"/>
  <concept>
    <code value="boolean"/>
    <display value="boolean variable"/>
    <definition value="A boolean variable is a variable which is defined to have only 2 possible values: True or False."/>
  </concept>
  <concept>
    <code value="continuous"/>
    <display value="continuous variable"/>
    <definition value="A continuous variable is one for which, within the limits the variable ranges, any value is possible (from STATO http://purl.obolibrary.org/obo/STATO_0000251)."/>
  </concept>
  <concept>
    <code value="dichotomous"/>
    <display value="dichotomous variable"/>
    <definition value="A dichotomous variable is a categorical variable which is defined to have only 2 categories or possible values (from STATO http://purl.obolibrary.org/obo/STATO_0000090)."/>
  </concept>
  <concept>
    <code value="ordinal"/>
    <display value="ordinal variable"/>
    <definition value="An ordinal variable is a categorical variable where the discrete possible values are ordered or correspond to an implicit ranking (from STATO http://purl.obolibrary.org/obo/STATO_0000228)."/>
  </concept>
  <concept>
    <code value="polychotomous"/>
    <display value="polychotomous variable"/>
    <definition value="A polychotomous variable is a categorical variable which is defined to have minimally 2 categories or possible values. (from STATO  http://purl.obolibrary.org/obo/STATO_0000087).  Suggestion to limit code use to situations when neither dichotomous nor ordinal variables apply."/>
  </concept>
  <concept>
    <code value="time-to-event"/>
    <display value="time-to-event"/>
    <definition value="time-to-event"/>
  </concept>
  <concept>
    <code value="not-specified"/>
    <display value="not-specified"/>
    <definition value="not-specified"/>
  </concept>
</CodeSystem>
```