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Automated Authority Control: Overview of Implementation

About the OCLC Authority Control Service
Records Processed by OCLC
Headings Processed by OCLC
Products Provided by OCLC

From: Authority Control Advisory Committee
Date: 20 January 1997


About the OCLC Authority Control Service

Our purpose in contracting with OCLC for automated authority control services is to update and correct headings and generate associated authority records for

To update and correct the headings on a library's bibliographic records, the OCLC software relies upon (1) headings and references in Library of Congress authority records (2) preferred headings from the OCLC Online Union Catalog (3) a catalog of heading variants derived from the OCLC Online Union Catalog and (4) sophisticated computer algorithms designed to recognize and correct a variety of errors. Together these features (1) minimize manual review (2) significantly boost the correction rate and (3) enable complex heading changes.

Another advantage of the OCLC service is that it generates transaction records instead of replacement bibliographic records. The OCLC transaction records modify only the affected fields in a bibliographic record, thereby allowing the database to remain completely dynamic while authority control processing is under way.

OCLC also offers a notification service, by which updates to those authority records that we have already received from OCLC are automatically sent to us, thereby affording us the opportunity to address our ongoing authority control needs.

Finally, the OCLC automated authority control service provides a number of useful reports, including (1) a report that lists headings that the OCLC software identified as problematic but could not correct and (2) a report that identifies significant changes to LC authority records.

Records Processed by OCLC

Initially approximately 2.6 million bibliographic records will be sent to OCLC for authority control processing. Excluded records include

Bibliographic records representing law library holdings only will be extracted separately and sent to OCLC for authority control processing at a later date.

Headings Processed by OCLC

The OCLC software processes the following headings:

The OCLC software does not yet process conference name headings, uniform title headings, or the title portion of name/title headings.

The name portion only (i.e. subfields a, q, b, c, and d) of subject headings that are tagged 600 with a second indicator of 4 will be processed by the OCLC software.

Subject headings that are tagged 690 or 691 will be processed by the OCLC software. If the heading matches an LC heading, it will be retagged as an LC heading (i.e. as a 650 or 651 with a second indicator of 0). If the heading does not match an LC heading, it will be retagged as a local heading (i.e. as a 650 or 651 with a second indicator of 4) and reported to us.

Subject headings that are tagged as 650 or 651 with a second indicator of 4 will not be processed by the OCLC software with a single exception: subject headings in approximately 5,000 Divinity Library "Missions" records that are tagged 650 with a second indicator of 4 will be processed. If the heading matches an LC heading, it will be retagged as an LC heading (i.e. as a 650 with a second indicator of 0). If the heading does not match an LC heading, it will be retagged as a local heading (i.e. as a 650 with a second indicator of 4) and reported to us.

Personal name headings in fields 100, 600, and 700 in the approximately 165,500 bibliographic records for which the corresponding RLIN record contains vernacular characters will be processed against LC forms of headings only and not against preferred forms from the OCLC Online Union Catalog.

Products Provided by OCLC

The OCLC authority control service will provide us with the following products:

We expect to receive approximately 1 million transaction records affecting at least 30% of the 2.6 million bibliographic records sent to OCLC for authority control processing. Click here to view some examples of transaction records.

It is difficult to estimate the total number of authority records that will be provided to us by the OCLC authority control service. Using the total number of authority records generated during the processing of approximately 50,000 of our bibliographic records as a base, and accounting for the fact that many headings are used more than once in our catalog, we estimate that we will receive as many as 2 million authority records from the OCLC authority control service.

Of those approximately 40% will be for personal name headings, 36% for Library of Congress subject headings, 13% for corporate name headings, and 11% for series headings. We will not receive authority records for MeSH headings. In addition to the authority records that are generated during the course of processing, OCLC will automatically provide us with a new authority record whenever a change is made to an authority record that we have already received.

This notification service, when coupled with one of the many reports that will be provided to us by OCLC, affords us for the first time the means with which to address our ongoing authority control needs. We will regularly receive a total of eight reports from OCLC, including


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