InstanceVariable

Generalization is RepresentedVariable.

Superclass hierarchy

Definition

Use of a represented variable within a data set.

Examples

  1. Gender: Dan Gillman has gender <m, male>, Arofan Gregory has gender <m, male>, etc.

  2. Number of employees: Microsoft has 90,000 employees; IBM has 433,000 employees, etc.

  3. Endowment: Johns Hopkins has endowment of <3, $1,000,000 and above>, Yale has endowment of <3, $1,000,000 and above>, etc.

Two InstanceVariables of a person’s height reference the same RepresentedVariable. This indicates that they are intended to: be measured with the same unit of measurement, have the same intended data type, have the same SubstantativeValueDomain, use a SentinelValueDomain drawn from the same set of SentinelValueDomains, have the same sentinel (missing value) concepts, and draw their Population from the same Universe. In other words, the two InstanceVariables should be comparable.

Explanatory notes

The InstanceVariable class inherits all of the properties and relationships of the RepresentedVariable (RV) class and, in turn, the ConceptualVariable (CV) class. This means that an InstanceVariable can be completely populated without the need to create an associated RepresentedVariable or ConceptualVariable. If, however, a user wishes to indicate that a particular InstanceVariable is patterned after a particular RepresentedVariable or a particular ConceptualVariable that may be indicated by including a relationship to the RV and or CV. Including these references is an important method of indicating that multiple InstanceVariables have the same representation, measure the same concept, and are drawn from the same Universe. If two InstanceVariables of a person’s height reference the same RepresentedVariable. This indicates that they are intended to: be measured with the same unit of measurement, have the same intended data type, have the same SubstantativeValueDomain, use a SentinelValueDomain drawn from the same set of SentinelValueDomains, have the same sentinel (missing value) concepts, and draw their Population from the same Universe. In other words, the two InstanceVariables should be comparable. The InstanceVariable describes actual instances of data that have been collected.


Subclasses


Properties

  • BlankString - A Blank string indicates missing. Comparison is based on lexical order.

  • EmptyString - An empty string indicates missing. Use in comparisons returns missing.

  • Rstyle - Codes drawn from NA and the IEEE 754 values of NaN -Inf +Inf. Comparisons return NA.

  • SASNumeric - codes drawn from . ._ .A .B .C .D .E .F .G .H .I .J .K .L .M .N .O .P .Q .R .S .T .U .V .W .X .Y .Z Sentinel code treated as less than any substantive value.

  • SPSSstyle - System missing (a dot) a set of individual values drawn from the same datatype as the SubstantiveValueDomain, and a range of values drawn from the same datatype as the SubstantiveValueDomain. Comparisons return system missing. Some functions substitute with valid values (e.g. SUM replaces missing values with 0).

  • StataNumeric - codes drawn from . ._ .A .B .C .D .E .F .G .H .I .J .K .L .M .N .O .P .Q .R .S .T .U .V .W .X .Y .Z Sentinel code treated as greater than any substantive value.

  • Unrestricted - No restrictions on codes for sentinel values. Use in comparisons is indeterminate.

Inherited Properties

Name

Description

Data Type

Multi- plicity

descriptiveText

A short natural language account of the characteristics of the object.

InternationalStructuredString

0..1

hasIntendedDataType

The data type intended to be used by this variable. Supports the optional use of an external controlled vocabulary.

ExternalControlledVocabularyEntry

0..1

unitOfMeasurement

The unit in which the data values are measured (kg, pound, euro).

:ref:``

0..1

agency

Agency expressed as filed with the DDI Agency ID registry [registry.ddialliance.org] with optional additional sub-agency extensions.

:ref:``

1..1

id

ID conforming to the allowed structure of the DDI Identifier and must be unique within the Agency.

:ref:``

1..1

isPersistent

Default value is false indicating that the content of the current version may change (may be in development mode). Set to true when the content of this version will no longer change.

:ref:``

1..1

isUniversallyUnique

Default value is false. If the id of the object was created as a Universally Unique ID (UUID) set to true.

:ref:``

1..1

localId

Locally used identifier unique with a specified context, such as a variable name within a dataset.

LocalIdFormat

0..*

version

Version number of the object.

:ref:``

1..1

versionDate

Date and time the object was changed expressed in standard ISO formats.

XSDdate

0..1

versionRationale

Reason for making a new version of the object.

RationaleDefinition

0..1

versionResponsibility

Contributor who has the ownership and responsibility for the current version.

:ref:``

0..1

definition
from Concept

Natural language statement conveying the meaning of a concept, differentiating it from other concepts. Supports the use of multiple languages and structured text.

InternationalStructuredString

0..1

displayLabel
from Concept

A structured display label providing a fully human readable display for the identification of the object. Supports the use of multiple languages and structured text.

LabelForDisplay

0..*

name
from Concept

A linguistic signifier. Human understandable name (word, phrase, or mnemonic) that reflects the ISO/IEC 11179-5 naming principles. If more than one name is provided provide a context to differentiate usage.

ObjectName

0..*

Associations

Multiplicity

Association

Navigable Class

Multiplicity

0..*

InstanceVariable_isBasedOn_RepresentedVariable

RepresentedVariable

0..1

0..*

InstanceVariable_measures_Population

Population

0..1

TBD

Diagram

TBD