4. Semantic Relationships used in Controlled Vocabularies

4.1 Semantic Linking | 4.2 Equivalency | 4.3 Hierarchy | 4.4 Associative

4.4 Associative Relationships (8.4)

This relationship covers associations between terms that are neither equivalent nor hierarchical, yet the terms are semantically or conceptually associated to such an extent that the link between them should be made explicit in the controlled vocabulary, on the grounds that it may suggest additional terms for use in indexing or retrieval. The relationship is symmetrical, and is generally indicated by the abbreviation RT (related term).

Example 114: Associative relationship notation (RT)

RT cytology

RT cells

The associative relationship is the most difficult one to define, yet it is important to make explicit the nature of the relationship between terms linked in this way and to avoid subjective judgments as much as possible; otherwise, RT references could be established inconsistently. As a general guideline, whenever one term is used, the other should always be implied within the common frames of reference shared by the users of the controlled vocabulary. Moreover, one of the terms is often a necessary component in any explanation or definition of the other; the term cells, for example, forms a necessary part of the definition of cytology.

Either of the following types of terms can be linked by the associative relationship:

a) those belonging to the same hierarchy
b) those belonging to different hierarchies

4.4.1 Relationships Between Terms Belonging to the Same Hierarchy (8.4.1)

Relationships are needed for terms belonging to the same hierarchy in various special situations, primarily to guide the user in locating the desired term. Relationships Between Overlapping Sibling Terms

Related Term (RT) references are required for sibling terms with overlapping meanings, such as ships and boats, where each of the terms can be precisely defined (so they do not form an equivalence set), yet they are sometimes used loosely and almost interchangeably. The user interested in one should be reminded of the other.

In the systematic section of a controlled vocabulary containing organized hierarchies (see 5.3.4), the method of display will bring the Related Term references together. The relationship should be indicated explicitly, however, in an alphabetical listing and in the alphabetic section of a hierarchical controlled vocabulary.

Example 115: Overlapping sibling terms hierarchical display

Example 116: Overlapping sibling terms alphabetical display Relationships Between Mutually Exclusive Sibling Terms

It is not necessary to interrelate all sibling terms. For example, there is no need to associate terms such as roses and daffodils, which share the broader term flowers, because the meaning of the terms does not overlap, i.e., they are mutually exclusive.

4.4.2 Relationships Between Terms Belonging to Different Hierarchies (8.4.2)

It is possible to establish many grounds for associating terms belonging to different hierarchies. Related Term references are often made between etymologically related terms, i.e., that contain the same root, but which do not represent the same kind of thing. The following are some representative examples of typical relational situations. For guidance on coding the precise nature of a relationship, see Z39.19 section 8.4.4. The following examples illustrate the types of associative relationships listed in Table 1 of 4.1.

Example 119: Process / Agent associative relationships

temperature control
RT thermostats

RT temperature control

RT hunters

RT hunting

Example 120: Process / Counteragent associative relationships

RT flame retardant

flame retardant
RT fire

RT anti-inflammatory agents

anti-inflammatory agents
RT inflammation

Example 121: Action / Property associative relationships

environmental cleanup
RT pollution

RT environmental cleanup

RT public opinion

public opinion
RT polling

Example 122: Action / Product associative relationships

RT cloth

RT weaving

RT tears

RT lacrimation

Example 123:Action / Target associative relationships

RT crops

RT harvesting

RT books

RT binding

Example 124: Cause / Effect associative relationships

RT bereavement

RT death

RT infections

RT pathogens

Example 125: Concept or Object / Property associative relationships

RT toxicity

RT poisons

RT surface tension

surface tension
RT liquids

Example 126: Concept or Object / Origins associative relationships

beluga caviar
RT Caspian Sea

Caspian Sea
RT beluga caviar

Socratic method
RT Greek civilization

Greek civilization
RT Socratic method

Example 127: Concept or Object / Units or Mechanisms of Measurement associative relationships

electric current
RT amperes

RT electric current

RT thermometers

RT temperature

Example 128: Raw Material / Product associative relationship

RT flour

RT wheat

RT lubricant

RT graphite

Example 129: Discipline or Field / Object or Practitioner associative relationships

RT mathematicians

RT mathematics

RT nervous system

nervous system
RT neurology

RT plants

RT botany

4.4.3 Node Labels for Related Terms (8.4.3)

In order to bring closely related concepts together in the alphabetical array under a given term, related terms may be divided into categories that do not form part of a logical hierarchy. These related terms should then be identified by a node label.

Example 132: Node labels for related terms

In this example, [operations] functions as a node label that describes a category or facet to which the related terms belong. Node labels used with narrower terms generally describe a characteristic or sub-division.

4.4.4 Specifying Types of Related Term References (8.4.4)

In certain controlled vocabularies, it may be considered desirable to refine Related Term references in order to make the nature of the relationships explicit.

Codes for such relationship indicators and their reciprocals may be developed locally. These local codes should be clearly explained and illustrated in the introduction or documentation of the published or machine-readable controlled vocabulary.

Go back to 4.1 Semantic Linking

| Table of Contents |
| 1. Why Vocabulary Control | 2. Principles | 3. Structures | 4. Semantic Relationships |
| 5. Displays | 6. When to use | 7. Examples of use | 8. About Z39.19 |
©NISO, 2005 http://www.niso.org/

Source: Based on ANSI/NISO Z39.19-2005 ISBN: 1-880124-65-3 
Guidelines for the Construction, Format, and Management of Monolingual Controlled Vocabularies