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A Type

This term is in the "new" area - implementation feedback and adoption from applications and websites can help improve our definitions.
StatisticalVariable represents any type of statistical metric that can be measured at a place and time. The usage pattern for StatisticalVariable is typically expressed using Observation with an explicit populationType, which is a type, typically drawn from Each StatisticalVariable is marked as a ConstraintNode, meaning that some properties (those listed using constraintProperty) serve in this setting solely to define the statistical variable rather than literally describe a specific person, place or thing. For example, a StatisticalVariable MedianHeightPerson_Female representing the median height of women, could be written as follows: the population type is Person; the measuredProperty height; the statType median; the gender Female. It is important to note that there are many kinds of scientific quantitative observation which are not fully, perfectly or unambiguously described following this pattern, or with solely terminology. The approach taken here is designed to allow partial, incremental or minimal description of StatisticalVariables, and the use of detailed sets of entity and property IDs from external repositories. The measurementMethod, unitCode and unitText properties can also be used to clarify the specific nature and notation of an observed measurement.
PropertyExpected TypeDescription
Properties from StatisticalVariable
measuredProperty Property The measuredProperty of an Observation, typically via its StatisticalVariable. There are various kinds of applicable Property: a property, a property from other RDF-compatible systems, e.g. W3C RDF Data Cube, Data Commons, Wikidata, or extensions such as GS1's.
measurementDenominator StatisticalVariable Identifies the denominator variable when an observation represents a ratio or percentage.
measurementMethod DefinedTerm  or
MeasurementMethodEnum  or
Text  or
A subproperty of measurementTechnique that can be used for specifying specific methods, in particular via MeasurementMethodEnum.
measurementQualifier Enumeration Provides additional qualification to an observation. For example, a GDP observation measures the Nominal value.
measurementTechnique DefinedTerm  or
MeasurementMethodEnum  or
Text  or
A technique, method or technology used in an Observation, StatisticalVariable or Dataset (or DataDownload, DataCatalog), corresponding to the method used for measuring the corresponding variable(s) (for datasets, described using variableMeasured; for Observation, a StatisticalVariable). Often but not necessarily each variableMeasured will have an explicit representation as (or mapping to) an property such as those defined in, or other RDF vocabularies and "knowledge graphs". In that case the subproperty of variableMeasured called measuredProperty is applicable.

The measurementTechnique property helps when extra clarification is needed about how a measuredProperty was measured. This is oriented towards scientific and scholarly dataset publication but may have broader applicability; it is not intended as a full representation of measurement, but can often serve as a high level summary for dataset discovery.

For example, if variableMeasured is: molecule concentration, measurementTechnique could be: "mass spectrometry" or "nmr spectroscopy" or "colorimetry" or "immunofluorescence". If the variableMeasured is "depression rating", the measurementTechnique could be "Zung Scale" or "HAM-D" or "Beck Depression Inventory".

If there are several variableMeasured properties recorded for some given data object, use a PropertyValue for each variableMeasured and attach the corresponding measurementTechnique. The value can also be from an enumeration, organized as a MeasurementMetholdEnumeration.
populationType Class Indicates the populationType common to all members of a StatisticalPopulation or all cases within the scope of a StatisticalVariable.
statType Property  or
Text  or
Indicates the kind of statistic represented by a StatisticalVariable, e.g. mean, count etc. The value of statType is a property, either from within (e.g. count, median, marginOfError, maxValue, minValue) or from other compatible (e.g. RDF) systems such as or
Properties from ConstraintNode
constraintProperty Property  or
Indicates a property used as a constraint. For example, in the definition of a StatisticalVariable. The value is a property, either from within or from other compatible (e.g. RDF) systems such as or
numConstraints Integer Indicates the number of constraints property values defined for a particular ConstraintNode such as StatisticalVariable. This helps applications understand if they have access to a sufficiently complete description of a StatisticalVariable or other construct that is defined using properties on template-style nodes.
Properties from Thing
additionalType Text  or
An additional type for the item, typically used for adding more specific types from external vocabularies in microdata syntax. This is a relationship between something and a class that the thing is in. Typically the value is a URI-identified RDF class, and in this case corresponds to the use of rdf:type in RDF. Text values can be used sparingly, for cases where useful information can be added without their being an appropriate schema to reference. In the case of text values, the class label should follow the style guide.
alternateName Text An alias for the item.
description Text  or
A description of the item.
disambiguatingDescription Text A sub property of description. A short description of the item used to disambiguate from other, similar items. Information from other properties (in particular, name) may be necessary for the description to be useful for disambiguation.
identifier PropertyValue  or
Text  or
The identifier property represents any kind of identifier for any kind of Thing, such as ISBNs, GTIN codes, UUIDs etc. provides dedicated properties for representing many of these, either as textual strings or as URL (URI) links. See background notes for more details.
image ImageObject  or
An image of the item. This can be a URL or a fully described ImageObject.
mainEntityOfPage CreativeWork  or
Indicates a page (or other CreativeWork) for which this thing is the main entity being described. See background notes for details.
Inverse property: mainEntity
name Text The name of the item.
potentialAction Action Indicates a potential Action, which describes an idealized action in which this thing would play an 'object' role.
sameAs URL URL of a reference Web page that unambiguously indicates the item's identity. E.g. the URL of the item's Wikipedia page, Wikidata entry, or official website.
subjectOf CreativeWork  or
A CreativeWork or Event about this Thing.
Inverse property: about
url URL URL of the item.

Instances of StatisticalVariable may appear as a value for the following properties
PropertyOn TypesDescription
measurementDenominator Observation  or
Identifies the denominator variable when an observation represents a ratio or percentage.
variableMeasured Dataset  or
The variableMeasured property can indicate (repeated as necessary) the variables that are measured in some dataset, either described as text or as pairs of identifier and description using PropertyValue, or more explicitly as a StatisticalVariable.



Example 1
Example notes or example HTML without markup.
As an example, the statement "According to the US Census ACS 5 Year Estimates,
the median age of women in San Antonio, Texas in 2014 was 34.4 years." can be
represented in JSON-LD.
Example encoded as JSON-LD in a HTML script tag.
<script type="application/ld+json">
  "@context": "",
  "@type": "StatisticalVariable",
  "@id": "Median_Height_Person_Female",
  "name": "Median height of women",
  "populationType": {"@id": "Person"},
  "measuredProperty": {"@id": "height"},
  "statType": {"@id": "median"},
  "gender": {"@id": "Female"},
  "numConstraints": 1,
  "constrainingProperty": {"@id": "gender"}
  "@context": "",
  "@id": "Observation_Median_Age_Person_Female_SanAntonio_TX_2014",
  "@type": "Observation",
  "name": "Median height of women in San Antonio, Texas in 2014",
  "description": "An Observation of the StatisticalVariable Median_Height_Person_Female in location: San Antonio, Texas, for time period: 2014",
  "variableMeasured": { "@id": "Median_Height_Person_Female" },
  "observationAbout": { "@id": "" },
  "observationDate": 2014,
  "value": 160,
  "unitCode": "CMT"

Structured representation of the JSON-LD example.