RBMS Manual / Thesaurus Construction and Maintenance Guidelines

RBMS Bibliographic Standards Committee

  1. Scope of the RBMS thesauri
  2. Form and choice of descriptors
  3. Compound terms
  4. Relationships between terms
  5. Print and screen display
  6. Thesaurus maintenance
  7. Sample Form

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The RBMS thesauri are constructed in accordance with the National Information Standards Organization's Guidelines for the Construction, Format, and Management of Monolingual Thesauri (NISO Z39.13, most recent edition published as Guidelines for the Construction, Format, and Management of Monolingual Thesauri, developed by the National Information Standards Organization; approved August 30, 1993, by the American National Standards Institute. Bethesda, Md.: NISO Press, c1994.) Because this standard incorporates a number of options and allows for certain local decisions, the Bibliographic Standards Committee has developed the following guidelines to assist Committee members as they maintain the existing thesauri and construct additional controlled vocabularies. This document must be used in conjunction with the current version of the national standard and supplements the information given in the introduction of each thesaurus. Committee members are strongly urged to review the published standard thoroughly before undertaking thesaurus maintenance projects.

The following sections roughly correspond to the chapters in Z39.19.

A. Scope of the RBMS thesauri

Many rare book libraries maintain local files recording aspects of items found in their collections such as form and genre, binding types, evidence of former ownership, etc. These files complement standard cataloging access points, such as author and topic, which emphasize the work over the artifact. The RBMS thesauri provide standard terminology for access to these items as called for in the Independent Research Libraries Association's Proposals for Establishing Standards for the Cataloguing of Rare Books and Specialized Research Materials in Machine-Readable Form (Worcester, Mass., 1979). There is the possibility of overlap among the six RBMS thesauri; some terms may be repeated in more than one thesaurus. Terms for works in some specialized rare book collections, especially subject collections, may have to be sought in other thesauri, or specialist thesauri may need to be developed. For example, RBMS has not undertaken comprehensive development of terms for graphic materials, maps, music, or legal materials. Each published thesaurus includes a list of works which have been used in preparing the thesaurus and to which users are referred for definitions of the terms presented.

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B. Form and choice of descriptors

The RBMS thesauri take their terminology and usage from a variety of sources, reflecting existing relationships between special collections librarianship and other fields of endeavor. Thus, the thesauri incorporate terms and usages from the antiquarian book trade and bibliographical scholarship, as well as from standard library usage (mainly as reflected in the glossary of AACR2). Literary warrant is the guiding principle for the selection of the preferred form of a descriptor. Each descriptor included in a thesaurus should represent a single concept or unit of thought. The scope of descriptors is restricted to selected meanings within the domain of the thesaurus.

A parenthetical qualifier is required to clarify the meaning of homographic terms used as descriptors, even when a descriptor is used in only one of its meanings within a specific thesaurus. The grammatical form of a descriptor should be a noun or noun phrase. Spelling should follow ACRL publications practice, which follows the latest edition of the University of Chicago Manual of Style. If variant spellings exist and are commonly recognized, each should be entered in the thesaurus, and a cross reference should be made from the non-preferred to the preferred form.

Node labels, or "dummy" terms, often expressed as phrases, are inserted into the hierarchical section of each thesaurus to indicate the logical basis on which a class has been divided. Node labels may also be used to group categories of related terms in the alphabetic section of a thesaurus. Use scope notes where desirable to explain a term's coverage, specialized usage, or rules for assigning it. A history note in a thesaurus provides the history of modifications to a term as to its scope, relationships, etc.

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C. Compound terms

Selection of a term consisting of more than one word as a descriptor is preferred to the use of a parenthetical qualifier with a single-word term if the compound term occurs in natural language. To be acceptable as a descriptor, a compound term should express a single concept or unit of thought and be capable of being arranged in a genus-species relationship within a hierarchy or tree structure. Guidelines for dealing consistently with compound terms are detailed in NISO Z39.19.

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D. Relationships between terms

Relationships of these kinds are included in the RBMS thesauri:

Relationship Indicator Abbreviation
Equivalence Use none or U
Used for UF
Hierarchy Broader term BT
Narrower term NT
Association Related term RT

The following example from Genre Terms includes a scope note and examples of the three types of relationships:

Plot-your-own stories
(Use for novels which have the reader choose from a number of options to develop the story.)
UF Game novels
BT Novels
NT Recreations

The hierarchical relationship is the primary feature that distinguishes a systematic thesaurus from an unstructured list of terms, such as a glossary. It is based on degrees or levels of superordination and subordination. The superordinate descriptor represents a class or a whole; the subordinate descriptor refers to a class's members or parts. In the thesauri, hierarchical relationships are expressed by the following notations:

BT (Broader Term) = label for the superordinate descriptor
NT (Narrower Term) = label for the subordinate descriptor

The hierarchical relationship covers three logically different and mutually exclusive situations: a) the generic relationship, b) the instance relationship, and c) the whole-part relationship. Every subordinate descriptor should refer to the same kind of concept as its superordinate descriptor, that is, both the broader and the narrower term should represent a thing, an action, a property, etc.

The generic relationship identifies the link between a class and its members or species. It is the most common hierarchical relationship in the RBMS thesauri. In this type of relationship the following statement can always be applied: "[narrower term] is a [broader term]." For example, Plays and Masques have a generic relationship, with Plays being the broader term and Masques the narrower term. All Masques are Plays; some Plays are Masques.

The instance relationship identifies the link between a general category of things or events, expressed by a common noun, and an individual instance of that category, often a proper name. Formats and Quarto format have an instance relationship, with Formats being the broader term and Quarto format the narrower term.

The whole-part relationship covers situations in which one concept is inherently included in another, regardless of context, so that the descriptors can be organized into logical hierarchies, with the whole treated as a broader term. Some examples of terms which would be related as whole-part are geographic locations; disciplines or fields of discourse; systems and organs of the body; and hierarchical organizational, corporate, social, or political structures. (There are no known examples of this type of relationship in the RBMS thesauri at the present time.)

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E. Print and screen display

The published NISO Z39.13 standard provides a wealth of information on the design of print and screen displays for thesauri; Committee thesaurus editors should pay careful attention to these sections of the standard. An overriding principle in the design of the format of a printed thesaurus is the minimization of double lookup, i.e., the need to consult more than one sequence. If in the future the Committee should decide to combine the six published thesauri into one, considerable editorial effort would be required. Any developments in the MARC authorities format for form terms must be taken into account in any such project.

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F. Thesaurus maintenance

The Bibliographic Standards Committee chair appoints one member of the committee to serve in the position of Thesaurus Editor. The Thesaurus Editor is responsible for becoming thoroughly familiar with the published standard (NISO Z39.19). Other responsibilities include maintaining term records, receiving proposals for new terms and changes to existing terms, verifying terms, receiving comments on the Section's published thesauri, and presenting proposals for new terms and changes to the Committee at appropriate intervals, generally on a two-year cycle.

Term records should be kept for all new terms considered by the committee. A term record is prepared for a previously published term whenever any change in the status of the term is considered, e.g. change in thesaurus hierarchy, scope note, related terms, etc. The history note in a term record records the date of entry of a descriptor. Term verification should be done by checking the reference works listed in the thesaurus introductions, as well as in the following published thesauri in order to avoid conflict where at all possible:

In addition to researching terms in appropriate works and doing term verification, it is also acceptable to circulate proposed thesaurus terms to individuals who are recognized authorities in a particular field. The Rare Books Group of the Library Association should also be consulted during the review process for new terms and changes, as well as for cross references for British variant terms and spellings.

The Bibliographic Standards Committee sends a representative to the Working Group on Form and Genre Vocabularies (and any such body which may absorb the work of the group), whose goal is the reconciliation of conflicting terms among the form and genre thesauri produced by members of the Working Group. Terms deemed to be non-reconcilable will be recorded as such and await another solution. The Committee should follow any developments regarding the problem of multiple thesauri in online systems.

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G. SAMPLE FORM

TERM RECORD FORM
RBMS BIBLIOGRAPHIC STANDARDS COMMITTEE

  1. Term:
  2. Thesaurus:
  3. Suggested by:
  4. Source of term: (Give specific indication of at least one place where the term was found. Include full citation.)
  5. Suggested scope note:
  6. Suggested broader term:
  7. Suggested related term(s);
  8. Term verification (reference works and thesauri consulted and results)

  9. History note:

  10. Date:
  11. Accepted form of term:
  12. Thesaurus:
  13. Broader term:
  14. Hierarchy:
  15. Not accepted:
  16. Use existing term
  17. Add as reference to existing term
  18. Sufficient literary warrant not found
  19. Term is outside scope of RBMS thesauri
  20. Other:
  21. Comments:

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