The first phase of MARS 2.0 Authority Control comprises a battery of routines that update and correct individual subfields and contiguous pairs of subfields, the purpose of which is to increase the likelihood of finding the appropriate authority match.
These corrections are based on a number of subfield update tables, maintained by MARS 2.0 authorities librarians.
MARS 2.0 subfield correction routines include:
MARS 2.0 uses a number of subfield correction tables to correct common errors in LC subfields
— Relations (General) with the United States
changes to:
— Relations — United States
MARS 2.0 also uses the subfield correction tables to correct common spelling errors in LC subdivisions:
| Error | Changes to | In Field / Subfield |
|---|---|---|
| Histroy | History | LC 6XX $x |
| Untied States | United States | LC 650 $z and 651 $a |
The subfield correction tables also support the expansion of outdated or invalid abbreviations in LC headings to the full form. Changes are made only when the outdated or invalid form is the entire text of the subfield:
| Outdated / Invalid | Changes to | In Field / Subfield |
|---|---|---|
| Hist. & crit. | History and criticism | LC 6XX $x |
| U.S. | United States | LC 651 $a, X10 $a, and 6XX $z |
| Econ. cond. | Economic conditions | LC 6XX $x |
MARS 2.0 uses a table to convert direct geographic subdivisions to the indirect form. Changes are made by the direct-to-indirect subfield conversion program only when the invalid form is the entire text of the $z and there is only one $z in the heading:
| Direct Subdivision | Changes to | In Field / Subfield |
|---|---|---|
| $z Paris | $z France $z Paris | LC 6XX fields |
| $z Jefferson Co., Kan. | $z Kansas $z Jefferson County | LC 6XX fields |
| $z Jefferson County, Kan. | $z Kansas $z Jefferson County | LC 6XX fields |
MARS 2.0 uses a table to convert chronological headings $y to their correct form. Corrections are made to spelling and punctuation as well as to format:
| Subdivision | Changes to | In Field / Subfield |
|---|---|---|
| $y Twentieth century | $y 20th century | LC 6XX fields |
| $z 20th century | $y 20th century | LC 6XX fields |
| $y 20th centry | $y 20th century | LC 6XX fields |
MARS 2.0 uses a subfield deletion table to eliminate canceled subfields from LC bibliographic headings, deleting subfields only when the invalid form is the entire text of the subfield:
| Deleted | Field / Subfield |
|---|---|
| Addresses, essays, lectures | 6XX $x |
| Addresses, sermons, etc. | 6XX $x |
| Collected works | 6XX $x |
The subfield deletion table also includes common misspellings and typographical errors:
| Error | Field / Subfield |
|---|---|
| Adresses, essays, lectures | 6XX $x |
| Addressses, essays, lectures | 6XX $x |
| Collected work | 6XX $x |
The subfield deletion table includes a section that prevents subfield conversions and deletions in headings meeting specific criteria.
Original:
— Yearbooks
New:
— Periodicals
*except when — Yearbooks is part of the subfield pair — Students — Yearbooks
Most errors in spacing, capitalization and punctuation are corrected as an integral part of the authority cleanup and authority matching processes. Routines are also run to correct spacing and punctuation on the following fields:
1XX, 240, 243, 245, 260, 4XX, 6XX, 7XX, 8XX
These processes eliminate any excess spaces in each field, makes sure each field has the correct punctuation within and between each subfield, and makes sure each field has ending punctuation.
Original: 100 10 $a Black, Adam, $d 1974- .$t Crested geckos 111 20 $a IEEE 1394 (FireWire) Workshop $d (2001, $c Berlin, Germany) New: 100 10 $a Black, Adam, $d 1974- $t Crested geckos 111 20 $a IEEE 1394 (FireWire) Workshop $d (2001 :$c Berlin, Germany)
While Authority Cleanup improves authority controlled headings using proprietary MARS 2.0 correcton tables, authority matching compares each authority controlled heading in your bibliographic records against authority record headings from any of a number of national and other authority files.
| Abbrev. | National Authority File | Updates | Size |
|---|---|---|---|
| NAF | Library of Congress Names | Weekly | 12,042,590 |
| SAF | Library of Congress Subjects | Weekly | 466,121 |
| CHILD/CYAC | Library of Congress Children's and Young Adult Program | Weekly | 13,131 |
| LCGFT | Library of Congress Genre Form Terms | Weekly | 2,627 |
| LCMPT | Library of Congress Medium of Performance Terms | TBD | 876 |
| MESH | National Library of Medicine | Annual | 658,232 |
| NLC-N | Library Archives Canada Names | Monthly | 2,185,630 |
| NLC-S | Library Archives Canada Subjects | Monthly | 11,616 |
| AAT | Art & Architecture Thesaurus | TBD | 56,876 |
| RBMSCV | *Updated* Rare Books and Manuscripts Section Vocabularies | TBD | 1,401 |
| TGM | Thesaurus for Graphic Materials | TBD | 8,590 |
| GSAFD | Guidelines on Subject Access to Individual Works of Fiction, Drama, etc | Frozen | 153 |
| FAST | Faceted Application of Subject Terminology | Quarterly | 1,855,837 |
| NASA | NASA Thesaurus | TBD | 18,336 |
| OLACVGGT | OLAC Video Game Genre Vocabulary | Frozen | 66 |
| EMBNE | National Library of Spain | TBD | 4,512,763 |
| QLSP | Queens Library Spanish Language Subject Headings | Frozen | 11,745 |
| ERIC | Education Resources Information Center (ERIC) Thesaurus | TBD | 4,552 |
| HOMOIT | Homosaurus | Semi-annual | 3,955 |
| ULAN | Union List of Artist Names | TBD | 402,765 |
| TGN | Thesaurus of Geographic Names | TBD | 2,991,045 |
| RVM | Répertoire de vedettes-matière | Monthly | 347,302 |
NOTE: As of September 2018, the Canadiana Name Authorities product from Library and Archives Canada has been discontinued. Library and Archives Canada is joining NACO and authority records are expected to be distributed via LC. Subjects Authorities are still distributed via LAC.
NOTE: RBMSCV (formerly known as RBMS) was released early 2023; the vocabulary and authorities is fully live in the Backstage system.
NOTE: Vocabularies and counts updated 11/25/2025.
Authority matching uses the headings in authority records to update or correct the bibliographic headings so they conform to current standards.
Authority matching is also the basis for providing full authority records for your local system. The goals of authority matching are to:
MARS 2.0 corrects and updates the full range of authority controlled headings. The following bibliographic headings / fields are included in MARS 2.0 authority control processing:
Name, Title, and Series Authority Controlled Headings |
|
|---|---|
Personal Names |
100, 700 |
Corporate Names |
110, 710 |
Conference Names |
111, 711 |
Uniform Titles |
130, 240, 730 |
Uniform Titles in a $t |
600, 610, 611, 700, 710, 711 |
Series |
400, 410, 411, 440, 800, 810, 811, 830 |
Subject Authority Controlled Headings |
|
|---|---|
Personal Names |
600 |
Corporate Names |
610 |
Conference Names |
611 |
Uniform Titles |
630 |
Topical |
650 |
Geographic |
651 |
Genre |
655 |
A number of MARC subfields are disregarded during MARS 2.0 authority matching. In the following headings, the volume designations in fields 810 and 440 $v, the heading linkage information in field 130 $6, and the ISSN in field 440 $x, are all examples of subfield information which is not under authority control:
810 _2 $a John Bartholomew and Son. $t Bartholomew world travel series ;$v 10. 130 _0 $6 880-01 $a ”Hsuuan lai his kan” his lieh. 440 _4 $a Romanica Gothoburgensia ;$v 12, 16 $x 0080-3863
The table below shows the subfields that are included in the MARS 2.0 authority matching process:
| MARC Field | Subfields Retained During Matching | Subfields Ignored During Matching |
|---|---|---|
| 100, 400, 700, 800 | a b c d f g h k l m n o p q r s t y z | e u v w x 2 3 4 5 6 |
| 110, 410, 710, 810 | a b c d f g h k l m n o p r s t y z | e u v w x 2 3 4 5 6 |
| 111, 411, 711, 811 | a b c d e f g h k l m n o p q r s t u y z | v w x 2 3 4 5 6 |
| 130, 830 | a d f g h k l m n o p r s t x y z | v w 2 3 5 6 |
| 730 | a d f g h k l m n o p r s t y z | v w x 2 3 5 6 |
| 440 | a n p | v w x 6 |
| 600 | a b c d f g h k l m n o p q r s t v x y z | e u w 2 3 4 5 6 |
| 610 | a b c d f g h k l m n o p r s t v x y z | e u w 2 3 4 5 6 |
| 611 | a b c d e f g h k l m n o p q r s t u v x y z | 2 3 4 5 6 |
| 630 | a d f g h k l m n o p r s t v x y z | w 2 3 5 6 |
| 650 | a b c d v x y z | e w 2 3 6 |
| 651 | a b v x y z | w 2 3 6 |
| 655 | a b c v x y z | e w 2 3 6 |
Headings from both your bibliographic records and the MARS 2.0 national authority files are normalized before they are compared for matching. MARS 2.0 uses the NACO normalization standard. During normalization:
Bibliographic Record Heading: $a Architecture $z Brazil $x S'ao Paulo (State) Normalized: ARCHITECTURE $ BRAZIL $ SAO PAULO STATE
Notice the subfield codes and the diacritic in S'ao Paulo have been discarded when constructing the normalized form of the heading.
Because subfield codes are ignored during the authority matching process, invalid subfield codes do not affect the matching and may be corrected during the process.
For this example, the normalized form of the established heading 1XX in the authority record is:
Authority Heading: $a Architecture $z Brazil $z S~ao Paulo (State) Normalized: ARCHITECTURE $ BRAZIL $ SAO PAULO STATE
Since the normalized forms of the bibliographic and authority headings are the same, the established form in the authority record replaces the form in the bibliographic record.
The bibliographic heading then contains the correct diacritic ~ instead of ' and the subfield code for S'ao Paulo has been corrected to $z.
The rest of the information contained in Step 3 details the matching options for your bibliographic and authority records. As with each step of this profile, these options are suggestions though each one can be customized according to your preference.
3.1 - 3.2 - 3.3 - 3.4 - 3.5 - 3.6 - 3.7 - 3.8 - 3.9 - 3.10 - 3.11 - 3.12 - 3.13 - 3.15 - 3.16 - 3.17 - 3.18