Discussion Paper 2002-DP03

DATE: January 8, 2002
REVISED:

NAME: Changes for FAST Subject Headings

SOURCE: OCLC, Library of Congress (LC)

SUMMARY: This paper presents the changes that are needed to accommodate the scheme for FAST subject headings as conceptualized by OCLC in the MARC 21 format.

KEYWORDS: FAST

RELATED:

STATUS/COMMENTS:

01/08/02 - Made available to the MARC 21 community for discussion.

01/21/02 - Results of the MARC Advisory Committee discussion - Most participants favored the requested changes and wondered if any other applications could use the proposed subfield $w/1 (Replacement complexity) values. There was some concern, however, about the use of Leader/06 code d (Deletion) for most library systems currently cannot load deleted records. Many participants wanted to know whether OCLC plans to distribute bibliographic records with FAST headings, however, OCLC representatives could not answer this at the time of the meeting. There is a need to show how FAST headings would be implemented in bibliographic records. One or two proposals will be presented during the annual 2002 meeting to discuss the use of FAST headings in both authority and bibliographic records.

Discussion Paper 2002-DP03: Changes for FAST subject headings

1. INTRODUCTION

OCLC is developing a subject vocabulary, FAST, for application to web resources that is based on LCSH but is intended to be easier to apply. The plan is that the FAST vocabulary could be applied to resources by non-catalogers and that resource discovery would then be possible through a controlled vocabulary, FAST. FAST's relationship with LCSH would facilitate cross file retrieval of resources to which LCSH has been applied.

In the following text, these terms have been used with the following meanings:

LCSH heading = a heading in the LCSH thesaurus
LCSH/FAST heading = a heading in the FAST thesaurus that has been adopted from LCSH
FAST heading = a heading in the FAST thesaurus that was newly created there

The FAST thesaurus contains records with LCSH/FAST headings (some valid and others invalid (Delete)) and records with FAST headings (some valid and others invalid). OCLC has worked with its FAST advisory group and the Network Development and MARC Standards Office to work within the MARC 21 format and minimize the format changes that would be needed to accommodate the FAST system as currently conceived.

2. FAST relationship to LCSH

2.1 Characteristics of the FAST system

FAST is built on LCSH and OCLC intends to keep the systems in synch. All LCSH headings will become FAST headings, at least initially.

The relationship of the new vocabulary to LCSH is the following:

• LCSH strings are broken into separate headings by type of component: topical, geographic, chronological, form.
  
  
• Topical components that are precoordinated in a single subfield would be left precoordinated (e.g. Concertos (String orchestra) and Rain and rainfall). Eventually some topicals, such as events, may be broken also into components (e.g., Bull Run, 2nd Battle of, Va., 1862 would become topical Bull Run, 2nd Battle, geographic Virginia - Bull Run and chronological 1862).
  
  
• LCSH topical components that are not precoordinated will be congruent with FAST headings (e.g., Astronauts).
  
  
• Geographic components would all be converted to indirect, generally under the smallest level in which they are fully contained that correspond to levels in the GAC list, (e.g., King Ranch (Tex.) would become Texas - King Ranch and Kenwood (Chicago, Ill.) would become Illinois - Chicago - Kenwood). Geographics would be keyed to GACs.
  
  
• Chronological components would be converted to all numeric (e.g., Great War, 1843-1852 would be two FAST headings, a topical Great War, 1843-1852 and a chronological 1843-1852; 20th century would become 1900-1999).
  
  
• Forms would be based on LCSH, including current work to extract forms from topicals.
  
  
• Separate FAST authority records would be made for all topical, geographic and form components, and perhaps a few chronological components that are term based (e.g., Carboniferous).
  
  
• Names and titles would be treated in a later phase.

Examples:

The initial FAST heading file will be the LCSH heading file (or some subset of same). These headings will be LCSH/FAST headings; later some LCSH/FAST headings will be made obsolete in favor of new faceted FAST headings derived from the LCSH/FAST heading.

2.2 Links between LCSH and FAST

Two kinds of special links between records/headings are needed in the FAST thesaurus file. Links from valid FAST headings to the obsolete LCSH/FAST heading from which it was derived are needed to facilitate expansion of a search to the LCSH form of a heading. Reverse links from obsolete LCSH/FAST headings to the FAST headings that replaced it are needed in order to channel updates of the LCSH heading to the derived FAST headings (see 2.3). Both links are needed in order to guide assigners who may be familiar with LCSH or are interested in the precoordinated components of related LCSH headings (see 2.4).

2.3 Updating FAST thesaurus from LCSH record updates

OCLC needs to be able to use updates from LCSH to update terms in the FAST thesaurus, and plans to do this by linking headings through the 7XX fields. No link is needed if the FAST heading is an LCSH/FAST as it is presumed that the LCSH/FAST heading record retained information about the source LCSH record, but if the heading is not LCSH/FAST, then a link from the FAST heading record back to the obsolete LCSH/FAST heading record is needed. OCLC feels the 7XX are adequate for this purpose. The 7XX will have a $2lcsh to identify the source thesaurus. (It is not yet clear in which FAST heading records these 7XX would reside since some facets may come from several LCSH strings.)

2.4 Obsolete headings in FAST

As a help to the cataloger/assigner (human or machine) of FAST terms, OCLC needs to be able to show what group of FAST headings are derived from facets of a former LCSH/FAST heading that has been atomized. When OCLC makes the LCSH/FAST heading record obsolete as they create replacement FAST headings for the facets, these obsolete records will be coded as Delete records in the FAST file but retained in the file as a guide to assignment of currently valid FAST headings. An assigner could go to the related LCSH/FAST heading record and from there determine appropriate (faceted) FAST headings or can go from a single FAST heading to the LCSH/FAST record for possible related terms. In the LCSH/FAST Delete record, OCLC needs to carry the authorized FAST replacement headings and prefers to have them in separate fields rather than in a formatted note such as field 682 (Deleted Heading Information) that is currently used for the information. These headings could be recorded in the 7XX fields with $2fast indicating they are the corresponding valid FAST headings.

The FAST headings in the 7XX field in the Delete record may in some cases be one-for-one replacements for each part of the LCSH heading (e.g., the LCSH string Bull Run, 2nd Battle of, Va., 1862 can always be replaced by the three headings Bull Run, 2nd Battle and Virginia - Bull Run and 1862) or they may represent a split of a string that disallows automatic replacement. OCLC states that "Nurses and nursing, a form that is obsolete in LCSH, would be an example of this type of split since there are still many bibliographic records that contain the heading in spite of the fact that it was changed many years ago. FAST will carry many old headings forms like Nurses and nursing. OCLC needs to be able to reflect that change in FAST and to distinguish (via the $w byte) it from the other changes made in FAST."

Indicating replacements versus splits is like the current Leader/05 (Record Status) where a delete is marked to indicate whether automatic replacement is possible or not. For the FAST implementation, OCLC has proposed that this information be carried at the field rather than the record level (as now) since only one part of the string may need to be marked to disallow automatic replacement. At the record level the simple value d (Deleted) would probably be used.

When FAST headings are created, causing an existing LCSH/FAST heading record to be changed to Delete (i.e., obsolete) status, a 4XX (See From Tracing Field) would be made in each record for the replacement FAST headings to serve as the reference to lead public users of records to the related LCSH headings. (The 4XX $w would be coded to indicate that the heading is an earlier form of the heading.) This is the usual model for authority control. The Delete records that are to be kept in the FAST thesaurus file are for assigner assistance, not for end users, however.

For subsequent changes to FAST headings, another Delete record might also be kept and the replacement heading(s) recorded in the 7XX fields, or the FAST record might be updated and a 4XX added for the previous form of the subject.

OCLC wants to use field 688 (Application History Note) to record the dates that a heading changed in FAST.

3. Field for Chronological Headings

FAST needs separate fields for each of the facets it uses. Most are already established: topical (150), geographic (151), and form (155), but a new field will be needed for the chronological facet. Tags 148 or 142 have been suggested. Field 045 (Time Period of content) is currently used for formatted time periods in the Bibliographic format. It could be used since OCLC does not generally plan to make authority records for the chronological facets, but in a few exceptional cases, authority records might be made so a place for them in the 1XX of the authority format is needed.

4. Kind of Record

Consideration was also given to changing the 008/09 (Kind of Record) from a (Established heading) to c (Traced reference) when the Record Status (Leader/05) was changed to Delete, but that would appear to serve no purpose. The fact that the record is a Delete record says the 1XX, which was formerly valid, is now invalid or obsolete. The c (Traced reference) value is intended to enable one to indicate in a valid record that the heading is invalid and was probably never valid. Changing the value to c would indicate that the heading was never valid. The value in the Leader/05 overrides the 008/09 as it currently does with Delete records. The 008/09 value would stay the same as it was when the record was valid in order to preserve the information that the heading was formerly valid

5. Summary of Changes

In summary, the following major change is needed:

• Define a new tag in the Bibliographic 6XX and the Authority 1XX, 4XX, 5XX, and 7XX fields for chronological headings. (The new tag could also be propagated to the Community Information and Classification formats, primarily to keep them coordinated.)
  
  
• Define a new position in subfield $w (Control subfield) of the 7XX fields:
  
  

  $w/1

  -

  Replacement complexity a - Heading from split b - Heading replacement n - Not applicable

• Description of codes s (Deleted; heading is split into two or more headings) and x (Deleted; heading replaced by another heading) of Leader/05 (Record status) changed to clarify that the deleted heading is considered obsolete within the thesaurus of the record.

6. Examples

Example 1

LCSH/FAST record:

LCSH/FAST record after it has been decomposed into 2 FAST records and one LCSH/FAST record:

FAST records:

LCSH/FAST record:

Example 2

LCSH/FAST record:

LCSH/FAST record after it has been decomposed into 3 FAST records:

FAST records:

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