[Enhance] LC records overlaying OCLC master records

[Greene,Richard]

The software that merges data and chooses which data to retain when an
LC record overlays an existing record is quite complex.  It is designed
to retain useful unique data from both records and the most
authoritative data possible, whenever that can be determined.  Due to
differences in cataloging practices, tagging, etc., the results are not
always what we expect but we are always looking for improvement.
Software will not always determine the best data and most useful data in
the same way as a human would.

You are correct about the non-Roman data.  We try to match up non-Roman
data to the corresponding roman-only field and link and retain both of
them.  If we find non-Roman fields that we cannot link to a roman-only
field, we usually merge it to the record with the expectation that a
user will find the record and link the fields correctly.

We have also taken steps to preserve series work as performed by our
users.  Tag 440 field will always be retained over tag 490 if the
contents are the same, even when an LC record replaces an existing
record.  We do not want to lose the information related to tracing.

Each tag that is considered for merging from one record to another has
its own set of rules.  The general rule is that, if the data is not
present in the record that will be kept, it will be merged from the
record being replaced.  Examples of this might be contents notes, call
numbers, and subject headings.  In the latter instance, we retain all
subject headings that are in a scheme not found in the retained record.
For example, if an LC record contains LC subject headings and matches to
a record that contains only Sears headings, the resulting WorldCat
record will contain the LC subject headings assigned by LC and the Sears
headings already in the record.  For additional information about the
fields that automatically transfer, see the Enhance Training Outline
(http://www.oclc.org/support/training/worldcat/enhanceoutline/) in
"Requirements, policies, and practices," Section E. Bibliographic
Duplicates, Number 6.


Unfortunately, the software will not always retain the most accurate and
up to date information.  If you have corrected a typographical error in
a record and the new version of the LC record has the same typo, the
software will put the error back into WorldCat and your correction will
be lost.  However, if you are adding information that improves access,
such as call numbers, non-LC subject headings, geographic area codes,
contents notes, etc., there is a good possibility that your enhancements
will be retained in the new record.

Rich Greene
OCLC, Inc.
6565 Kilgour Place
Dublin, OH 43017
614-764-6154
email:  richard_greene at oclc.org 

-----Original Message-----
From: enhance-bounces at mailman1.u.washington.edu
[mailto:enhance-bounces at mailman1.u.washington.edu] On Behalf Of D.
Brooking
Sent: Thursday, October 16, 2008 6:46 PM
To: enhance at u.washington.edu
Subject: [Enhance] LC records overlaying OCLC master records


Dear Enhancers,

I need to have a review of what could happen should LC make any changes
to a record that would then get redistributed, including to OCLC. Which
if any fields are protected from overlay in OCLC?

I am concerned because we are increasingly making enhancements and
corrections to LC records in the area of international studies, changes
that don't result in a change in encoding level.

I seem to remember that non-Roman fields that LC lacks will not get
wiped out, and that some kind of series protection is now there so
series don't all revert back to 490s. But what about other things? LC
records are treated differently than all others, but I am not sure this
makes sense any longer in the new "network-level" environment we are
trying to build.


************
Diana Brooking             (206) 685-0389
Cataloging Librarian       (206) 685-8782 fax
Suzzallo Library           dbrookin at u.washington.edu
University of Washington
Box 352900
Seattle WA  98195-2900
_______________________________________________
Enhance mailing list
Enhance at u.washington.edu
http://mailman1.u.washington.edu/mailman/listinfo/enhance