The information in this section does not pertain directly to the profile steps, but it is important to your understanding of MARS 2.0 authority control processing.
LC authority records are constructed so that they are naturally self deblinding:
established heading: 150 $a Fishing see from heading: 450 $a Sport fishing see from also heading: 550 $a Wildlife-related recreation
See from xrefs
Most ILS generate a heading based on the 150 and 450 fields in the authority above:
Sport fishing See Fishing
The See heading informs a patron searching for records using the entry term Sport fishing that works related to that topic can be found under the preferred term Fishing.
This record is self deblinding since the display Sport fishing, See Fishing is not generated unless you have works cataloged under that term.
If you have works cataloged under the term Fishing, MARS 2.0 will include the authority record above in your authority file.
If you have no works in your catalog under the topical subject heading Fishing, MARS 2.0 does not distribute the Fishing authority record to you.
See from also xrefs
In addition to the See cross-reference, most local systems will also generate a See Also display based on fields 150 and 550 in an authority record:
Wildlife-related recreation See also Fishing
The See Also heading informs a patron searching for works related to Wildlife-related recreation that a search for the more general term Fishing should be considered.
The See Also display helps patrons find works in your collection that may be related to the concept they are seeking. Whether your collection contains any works on the specific heading Wildlife-related recreation, the provision of the additional entry term is beneficial to the patron.
Deblinding See Also xrefs would prevent the above See Also display from being generated, usually by either deleting the 5XX xrefs from the authority records or changing the 5XX tag to a 4XX if your collection contains no works cataloged under that specific heading.
MARS 2.0 staff does not recommend the removal of 5XX fields from authority records, or converting a 5XX tag.
The available See Also xref in your ILS will direct the patron to the related term of Fishing found in your catalog.
Then if you were to later acquire works cataloged under Wildlife-related recreation, the necessary See Also display would not appear, as the underlying 550 field had been removed from the authority record. Or a See xref would be generated incorrectly indicating your catalog possessed no works on the primary heading.
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