Authority Control

Authority Record Matching

After preliminary processing is completed, compressed "match keys" from catalog record headings are compared against an index of match keys extracted from 1XX/4XX fields in LC and LTI authority records. Links to LC authority records take precedence over links to LTI authority records.

To increase authority record links, certain tag variations in catalog record headings are ignored during match key comparisons. For example, if a corporate name (110/610/710/810 field) has been improperly tagged as a personal name (100/600/700/800 field), the link will not only be made with the proper form of the heading, but the incorrect tag will be corrected automatically.

Some headings do not link because of incorrect subfield coding, as when a chronological subdivision ($y) is miscoded as a topical subdivision ($x) and vice versa. LTI scans for and corrects such problems.

A common reason headings fail to match an authority record is because a Library of Congress authority record does not exist for the heading. Name authority records date back only to 1977 and subject authority records are a reflection of LCSH rather than an exhaustive file of subjects and subject subdivisions appearing in MARC records. Almost no name headings and only a fraction of the thousands of topical, form, chronological, and geographic subdivi-sion headings receive their own LC subject authority records.

Other initial linkage failures are caused by typographical errors, headings constructed under earlier cataloging rules, variant treatment of names with prefixes, and direct versus indirect division of geographic names. Most of these headings are corrected and linked to an authorized heading. To achieve these links, catalog record headings are submitted to repeated manipulations and checks by computer.

Pseudonym Preservation

In some situations libraries may want to override links to LC authority records. For example, the library may want titles written under the pseudonyms Peter Curtis and Juliet Astley to appear in the catalog record under these names rather than Norah Lofts.

Public libraries having extensive collections of older fiction in particular may prefer title page cataloging because fiction is generally shelved by the author's name as it appears on the book's title page. LC's decision to adopt a revision to AACR2 Rule 22.2C after 1987 means that a separate authority record is issued for each pseudonym used by an author. Pseudonyms found in post-1987 authority records, as well as authority records corrected after that time, do not appear in LTI's preserved pseudonym list since they are already preserved without any intervention by LTI.

For libraries wishing to retain an author's name as it appears on the book's title page, LTI maintains a file of pseudonymous authors. At this point there are fewer than 80 names on this list and it is quite possible that separate authority records will never be distributed for most of these authors.

Inclusion on this list prevents the library's heading from being linked to an LC name authority record. Main entry (1XX) headings in records are checked against the pseudonym file during the final linking process. Headings on LTI's preserved pseudonyms list are not converted to the "real" name present in pre-1988 LC authority records. LTI software recognizes most variations of the pseudonyms and corrects those variations to the standard form of the pseudonym.

Name Authority Matching

Initially, many personal name headings (100/600/700/800) fail to link with an authority heading because of variations in the fullness of birth and death dates or variations in "titles and other words associated with the name" (subfield $c) information. Tests are applied to personal, corporate, and conference name headings that disregard minor variations to maximize authority record links. For example, when the match key created for the personal name heading Allingham, Helen Paterson, $c"Mrs.William Allingham,"$d1848- fails to link with an authority record, the heading is checked without subfield $c data. If the heading still does not link, another match is tried which accepts any death date in $d, if the birth date matches. This second match key refinement allows a valid link with the LC authority heading Allingham, Helen Paterson, $d1848-1926.

When a link is found to an authority record, the form in the authority record replaces the form in the incoming heading. For many years, libraries that deviated from Library of Congress practice and added known death dates to headings for famous people had either to accept the replacement with an open date or to perform ongoing local maintenance to such headings. With the adoption of LCRI 22.17, authority records for several hundred well-known names had death dates added in a project that spanned most of 2006, with new additions weekly. Libraries will no longer have to re-edit authorized bibliographic records to add this information, nor be concerned with the loss of this data in the first place.

Title Authority Matching

Title portions of name/title headings (X00/X10/X11 fields containing $t or $k) and uniform title fields (130/240/630/730/830) undergo special treatment to increase matches. In each case the title portion of the field is checked for "floating" elements which are corrected and validated separately. These include dates ($f), languages ($l), medium designator ($h), and versions ($s). Music headings also have the arrangement statement ($o), key ($r), and medium of performance ($m) corrected and validated.

Special Series Processing

While untraced series (i.e., those tagged as 490 with a first indicator of '0') have generally been excluded from standard authority control processing, LC's decision effective June 1, 2006 to discontinue providing controlled access to series in bibliographic records and to cease creation of series authority records makes it important that libraries have a mechanism to continue to treat series as controlled headings. The number of series authority records has grown less rapidly since LC ceased to create them. However, the backfile of existing LC series authority records, as well as new national-level records being created by NACO libraries, continues to be available for authorization of series headings. Over the years LTI has also created many series authority records in-house, used to match incoming headings in the absence of a national-level record.

Libraries are encouraged to take advantage of LTI's no-charge "untraced series" option that allows for the authorization of 490 0 fields. Using this option, if the first indicator in a 490 field is set to '0', LTI changes the indicator value to '1' and generates an appropriate 8XX (traced series) field. If the newly created 8XX field is linked to an authorized heading during authority control, both the 490 1 and authorized 8XX fields are retained.

If the LTI-created 8XX field remains unlinked following authority control, libraries can opt to either: (1) delete the LTI-created 8XX field and change the 490 first indicator back to '0'; or, (2) retain the 490 (traced differently) series with a first indicator of '1' and the LTI-created (but unlinked) 8XX series heading. When the form in the 8XX field cannot be matched to an authority record, LTI recommends that the 490 1 / 8XX combination be retained. Should an authority record later be distributed, it will be provided to the library when the heading is authorized during a continuing [AEX or AUP] authority control run. For libraries retaining the 490 1 / 830 series, we further advise that 490 1 fields not be indexed. The same advice would apply to 490 0 fields but, under this option, none of these fields will remain in the database.

Subject Authority Matching

All subject headings are first processed through a "subject fix" program that corrects common errors in subject headings and fixes incorrect and obsolete topical, chronological, and geographic subdivisions.

Using tables of commonly occurring names, jurisdictions, subjects, and subject subdivisions, abbreviations are expanded and subjects and subject subdivisions are modernized. For example:

Headings are then matched against the LC subject authority file. Because most subject subdivisions are not represented as separate LC authority records, LTI maintains tables of "free floating" topical, form, chronological, and geographic subject subdivisions.

Pattern headings in these tables are used to validate thousands of headings that would otherwise not link. Headings that have not fully linked are broken into their component parts and tested against subject authority records and tables of validated floats.

Unlinked personal, corporate, conference, or geographic name (600/610/611/651 fields) headings are checked against the LC name authority file (ignoring subfields $v, $x, $y, and $z) to validate the form of name wherever possible. Later, subfields $v, $x, $y, and $z are validated against float tables. Where libraries have used double dashes, in place of appropriate subject subdivision coding, LTI's software recognizes the subdivision and inserts the proper subfield code.

Geographic Subdivisions

LTI maintains a file of 170,000 correct indirect geographic subdivision forms. In addition, software is used to convert direct geographic subject subdivisions into indirect form. Geographic subject subdivisions are identified and fixed even when $z data has been improperly coded as $x or $y or appended to $a. Where necessary higher level jurisdictions are inserted. For example, the topical subject heading:

and the heading:

Through limited review processing, LTI is presently linking on average between 96% and 99% of subject headings for academic and public library databases.

Obsolete LC headings replaced by two or more valid headings (i.e., "split" headings) present special authority control problems. For example, the topical heading Negroes was replaced by the headings Blacks and Afro-Americans; then, in 2001, Afro-Americans was changed to African Americans. In some cases the correct division of split headings can be deduced from other parts of the heading. Thus, LTI automatically converts headings having the structure "Negroes$z[State]" to "African Americans$z[State]," e.g., the heading Negroes$zMississippi is changed to African Americans$zMississippi. The heading Negroes followed by a country other than United States is changed to Blacks.

Where there is insufficient information to make the split, LTI links all occurrences of the obsolete heading to the broader heading. For example, "Crime and criminals" will go to "Crime." However, if "Crime and criminals" were followed by a "Biography" subdivision, the new heading would be changed to "Criminals." LTI's handling of splits is not affected by whether the job is limited or full review.

Form Subdivisions

In early 1999 the Library of Congress began to issue authority records with form subdivisions in $v, heretofore coded $x. LTI analyzed LC's form subdivision usage patterns and created processing guidelines for the assignment of $v. Briefly, when a heading contains a subdivision that is valid for use as a form subdivision and it is the last subdivision in the heading, it will be coded as $v, except in certain special cases, e.g., when there is a full link to an LC authority record containing the subdivision in $x. Conversely, if the subdivision can be $v, but is not the last subfield in the heading, it will not be changed to $v. Exceptions to the latter rule are if it has been identified as a special case which will take a $x following a $v, e.g., $vDictionaries$x[language] or when it is permissible to follow $v with another $v.

Role of Added Cross-References

An important factor to LTI's ability to offer a guaranteed link rate is a supplemental file of 3.8 million added cross-references. Name headings con- stitute 89% of the cross-references; the remaining 11% are subject cross-references. Each reference refers from the form of the heading used in the catalog record to the correct form used in the LC authority record.

These references are not added to LC authority records, but rather cumulated in separate files that are processed after linking to LC authority records, but before linking to LTI authority records. For example, when an LTI editor links manually the library heading Marquand, John P., $d1893- . to the LC authority record heading Marquand, John P.$q(John Phillips),$d1893-1960., that cross-reference is saved and applied subsequently to other library databases. Because not all cross-references can be applied to every database, editor-created cross-references undergo a second review prior to being added to LTI's cross-reference file.

Added cross-references serve two purposes. First, they correct the heading in the library database that prompted their creation. Second, when the same unlinked heading appears in another customer's database, that heading is automatically linked to the proper authority record, thereby reducing the number of headings that require manual review and allowing LTI to focus on the research and establishment of headings that are genuinely new. Because so many machine-readable records are derived from shared cataloging databases, these supplemental cross-references play an important part in LTI's authority control routines.

When the complete catalog record heading cannot be validated or linked to an authority record, an attempt is made to link portions of the heading. Through limited review processing, LTI is presently linking 90% to 96% of name, title, and series headings, either fully or partially to a nationally distributed authority record, for most academic and public library databases.

LTI Authority Record Linking

LTI maintains its own file of name and subject authority record headings established in accord with AACR2 and LC cataloging practice. Presently, there are 2.2 million LTI authority records. These authority records are created from validated but unlinked headings that have appeared in library databases. To qualify as an LTI authority record heading, the heading must meet three criteria: 1) it has been searched thoroughly but not found in the LC authority files, 2) it is coded properly (tags, indicators, and subfield codes), and 3) it conforms to national cataloging standards. If an LC authority record is later distributed for the heading, the LTI authority record is deleted. Library headings are matched against LTI authority record headings only after they have failed to link to an LC authority record heading. In a typical database, LTI authority records validate 3% to 4% of the headings and most of these represent no change to the source heading-i.e., the heading in the library's catalog record is identical to the LTI authority record heading.

A recent analysis of a one million record database showed that 3.2% of the controlled headings were validated against LTI authority records. Six out of seven of these headings were not changed by LTI-i.e., the headings appeared in the authorized catalog records exactly as they appeared in the library's source records. Where changes did occur, in 1,300 [0.0003%] out of 4.4 million headings, the variations were primarily attributed to content designation fixes and minor differences in the headings. This includes insertion of $d (date) and $q (fullness of name) in personal names, $b in corporate names, and tagging errors in subjects. Again, the sole purpose of LTI authority records is not, in the absence of a nationally distributed authority record, to change a library's headings; but rather to reduce the number of unlinked library headings that need to be reviewed by LTI editors. By eliminating headings that have already been reviewed in a prior job, editors are able to focus more attention on the unlinked headings that can most benefit from manual review. Libraries that plan to examine the unlinked headings report also benefit from exclusion of these valid headings from that report.

Review of Unlinked Headings

After all possible machine matches have been made, LTI editors selectively search targeted unlinked headings in the LC name and/or subject authority file. Sometimes an editor needs to view the bibliographic record(s) from which headings were extracted to determine if they represent the same person or entity. Editors have access to a fully indexed version of the library's database and can display catalog records to resolve ambiguous headings.

Incorrect tags and subfield codes, typographical errors, omitted or incorrect dates, and related problems are corrected manually and resubmitted for relinking. Where the same heading is linked to obviously different bodies, as sometimes occurs with acronyms, the editors temporarily force the correct link for that specific database.

Unlike authority vendors that have a policy of treating the same name heading with and without dates as distinct headings, in an LTI authority controlled database one will almost never find variant forms of the same heading. In backfile processing LTI editors merge all variant forms of a heading whenever they are determined to be the same person or entity. Failure on the part of the authority control vendor to merge such headings defeats the purpose of authority control.

Next: Authority Record Distribution