Difference between revisions of "Profile Guide Step 3.9"
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Revision as of 13:12, 6 August 2008
National Authority File MARS 2.0 processing can match bibliographic headings against headings in the National Library of Medicine’s MeSH Authority File. The current MeSH authority file contains just over 580,000 authority records for descriptors, qualifiers, and descriptor/qualifier combinations. Over 300,000 new and updated authority records are issued by NLM in the MeSH annual update.
Contents
Step 3.9 Question
Fields Matched
The following fields are matched against the NLM MeSH Authority File:
- Only those with a 2nd indicator of ‘2’ are MeSH Headings
Ignore / Do Not Process
Some libraries have catalogs that do not contain subject headings coded as Medical headings. Other libraries have bibliographic records in their catalog that contain Medical headings, but their local system is profiled to exclude them from the OPAC indexes. Most libraries in which the Medical headings are not used and are not causing any problems for patrons select the “Do Not Process” option for Step 3.9. Under this option, MARS 2.0 ignores the Medical headings during Authority Control Processing.
Remove Without Processing
Under this option, all subject headings with a second indicator of 2 are removed from the bibliographic records.
Databases and Search Order
If you choose to have your Medical headings processed, you also have the choice of which database to search against as well as in which order the databases should be searched. The two databases available to search are:
- NLM MeSH Authority File
- LC Authority File
- Other National Files available (please check with with your Project Manager)
Search NLM MeSH Authority File Only
In this option, MARS 2.0 processes match the MeSH headings against the MeSH Authority File. For those headings that match a heading in the MeSH Authority File, the indicator remains as a 2. Headings that match a cross-reference in the MeSH Authority File are flipped to the established form of the heading and the second indicator is again retained as a 2. After the matching is completed, all remaining MeSH headings (i.e., those that did not match a heading in an MeSH authority record) are retained in the records.
Search NLM MeSH Authority File Against LC Adult Only
In the catalogs at some libraries, the presence of Medical headings in their bibliographic records creates duplicate and sometimes confusing index entries for patrons. These libraries may wish to consider choosing this option:
In this option, MARS 2.0 processes first match the Medical headings against the LC Authority File as if the headings had a second indicator of 0 instead of 2. For those headings that match a heading in the LC Authority File, the indicator is changed from 2 to 0. Headings that match a cross-reference in the LC Authority File are flipped to the established form of the heading and the second indicator is again changed from 2 to 0. After the matching is completed, all remaining Medical headings (i.e., those that did not match a heading in an LC authority record) are removed from the records. Or, you could choose that any Medical headings that fail to match an LC authority record are retained in the bibliographic record with the original second indicator value of 2.
Examples
If a library requested that their MeSH headings be matched against LC only, and a bibliographic record contained the following subject heading:
650 2 $aNeoplasms.
MARS 2.0 programs would compare the heading against the LC Subject Authority File. The heading would match a cross-reference (4XX field) in the LC authority record sh 850138553:
150 $aTumors 450 $aNeoplasms
The heading in the bibliographic record would be converted to the following new form:
650 0 $aTumors.
When a subject heading is being converted from MeSH to LC, MeSH subdivisions that are not part of the matching LC authority record are retained in their original form. For example, there is no LC authority record for the full MeSH heading below:
650 2 $aNeoplasms$xdiagnosis.
The subfield $a would match on the same LC authority record sh 850138553 shown above (only if the library has requested MeSH headings matched exclusively against LC headings). A higher-level conversion would occur in which the subfield $a is converted to the LC form, while the subfield $x is retained in its original form. The final heading would be:
650 0 $aTumors$xdiagnosis.
Search MeSH First, LC Adult Second
Some libraries prefer to search their Medical authorities against the NLM MeSH Authority File first. Any matches found will update the heading, but the second indicator value will remain as 2. However, unmatched Medical authorities could then be searched against the LC Authority File. Any matches found during this procedure would change the value of the second indicator from 2 to 0. Choosing this option would look like this for Step 3.9:
In this option, MARS 2.0 processes would retain unmatched Medical headings, with a second indicator value of 2, to be searched at a later date by the library (of course, Remove unmatched headings could instead be chosen above if the library preferred that option). Matched headings for this option could either have a second indicator value of 2 for matches found within the NLM MeSH Authority File or a second indicator value of 0 for matches found within the LC Authority File. This option is particularly useful for libraries interested in updating and retaining their Medical headings if possible, with the option to upgrade them to LC headings if there is no match during the first pass against the NLM MeSH Authority File. Changing the search order (LC Adult=1, MeSH=2) reverses the order in which headings are matched.
Example
In the headings below, this option would result in a change in form of the 610 heading based on the cross-reference in LC authority record n 85363832 and a change in the second indicator of the 610 field from:
610 22 $aJohns Hopkins University.$bSchool of Medicine.$bDivision of Medical Genetics. changed to: 610 20 $aJohns Hopkins University.$bDivision of Medical Genetics.
Related authority record:
010 $an 85363832 110 2 $aJohns Hopkins University.$bDivision of Medical Genetics. 410 22 $aJohns Hopkins University.$bSchool of Medicine.$bDivision of Medical Genetics.
If your requirements either fall outside of these options or you have questions about Step 3.9, please contact your MARS 2.0 support representative.
