DATE: November 15, 1997

NAME: Elimination of tag conflicts in the USMARC Bibliographic, Community Information, and Holdings formats

SOURCE: Library of Congress

SUMMARY: This proposal suggests changing the field tag for special coded dates currently recorded in control field 004 in the Community Information format and field tag 551 for the entity and attribute information note in the Bibliographic format to eliminate conflicts in the definition of field 004 in the Holdings and field 551 in the Community Information formats.

KEYWORDS: Budget Note; Coded Dates Fixed Field (CI); Control Number for Related Bibliographic Record (HD); Entity and Attribute Information Note (BD); Field 004 (CI,HD); Field 046 (BD,CI); Field 551 (BD,CI); Special Coded Dates (BD,CI); Type of Date Code, Date 1, Date 2 (B.C. Dates)) (BD)

RELATED: DP50 (June 1991); 92-1 (January 1992); 94-17 (May 1994)


11/15/97 - Forwarded to USMARC Advisory Group for discussion at the January 1998 MARBI meetings.

1/11/98 - Result of USMARC Advisory Group discussion - Approved. LC will investigate whether defining subfields $a-$e in the Community Information Format and subfields $f-$i in the Bibliographic Format will be problematic for either set of users.

2/11/98 - Result of final LC review - Approved.

PROPOSAL NO.98-4: Elimination of tag conflicts


Recent work to develop an implementation of the Standard
Generalized Markup Language (SGML) for USMARC has involved
scrutiny of all five formats from a data element point of view. 
The SGML development work resulted in the creation of two USMARC
data element supersets; one for the elements shared by the USMARC
Bibliographic, Community Information, and Holdings formats, a
second for the USMARC Authority and Classification formats. 
Within these data element supersets some slight variations in
data element names and scope were found.  In most cases the
differences involve similar data elements that are shared between
formats and can be remedied by minor editorial name changes.  Two
significant conflicts were identified in the
bibliographic/community information/holdings format superset
where the same field tag was used for very different kinds of
data.  In the Community Information format, field 004 (Coded
Dates Fixed Field) differs considerably in content and use from
the Holdings format field 004 (Control Number for Related
Bibliographic Record).  In the Bibliographic format, provisional
field 551 (Entity and Attribute Information Note), differs
considerably in content and use from the Community Information
format field 551 (Budget Note).  This proposal suggests changes
to the Bibliographic and Community Information formats to
eliminate these tag assignment conflicts.


When the project for a USMARC Format for Holdings Data was first
discussed it included a design principle that whenever data was
the same or similar to that in the Bibliographic format, the same
tag as found in the Bibliographic format was to be used. 
Additionally, for data that could not be accommodated by an
existing Bibliographic tag, an unused (in Bibliographic and
Holdings) tag or tag group was to be designated in the new
format.  This principle was extended to indicator values and
subfield codes.  As the result of a similar basic design
principle, the data elements defined in the USMARC Format for
Community Information, which was first discussed in 1991 (in
Discussion Paper No. 50) and finally approved in 1992 (with
Proposal 92-1), carried over a large number of existing USMARC
Bibliographic data elements with similar names and definitions.

When the Community Information format was developed, however, the
need to extend the "no overlap" rule to Holdings was overlooked. 
Thus it was not observed that field 004 was used in Holdings and
unavailable for use in Community Information.  Likewise, an
oversight in Proposal No. 94-17 (Changes to the USMARC
Bibliographic Format to Accommodate the Content Standards for
Digital Geospatial Metadata (CSDGM)) resulted in field tag 551
being approved for the Bibliographic format although it had been
used for a different purpose in Community Information.

The development of the USMARC SGML Document Type Definition
(DTD), which handles the superset of bibliographic, community,
and holdings data elements by a single SGML DTD, has brought
attention to these problems in tag assignment.  It is 
technically possible through complex content modelling in the
MARC Bibliographic DTD to work around these problems, but that
solution would make the use of SGML for USMARC difficult.  It
also would not alleviate the problems for systems attempting to
integrate these 3 formats in one environment, as was intended.

Solution for field 004

Field 004 could be changed in either the USMARC Community
Information or Holdings formats.  Changing the Holdings format to
prescribe using a field other than 004 for the control number of
a related bibliographic record would be extremely disruptive to
current implementations of the Holdings format.  The 004 in
Holdings is a solution for handling record links between
bibliographic and holdings data for many years.  Considering the
more limited implementation of the USMARC Community Information
format, and the fact that the oversight in tag assignment was
made during its development, a change to the Community
Information format to use a tag other than 004 would probably
have lesser impact.

The Community Information 004 is currently defined thus:

004   Coded Dates Fixed Field  (NR)
Character Positions
 00-07   Action date
    These eight character positions (yyyymmdd) contain the date
    the record needs to be looked at again.
 08-15   Purge date
    These eight character positions (yyyymmdd) contain the date
    the information should be removed from the system as it is
    no longer relevant.
 16-23   Beginning date of event or program
    These eight character positions (yyyymmdd) contain the
    beginning date of an event or program.
 24-31   Ending date of event or program
    These eight character positions (yyyymmdd) contain the
    ending date of an event or program.

The content and structure of the four dates possible in the
Community Information field 004 do not require that a control
field in the 00X range be used.  Other MARC dates and codes are
currently recorded in a variety of number fields in the 01X to
04X range, yet the remaining open tags in that range are few. 
Considering the characteristics of the dates currently prescribed
for Community Information format field 004, the scope of the
existing USMARC field 046 (Type if Date Code, Date 1, Date 2
(B.C. Dates) could be expanded to include them.  Field 046 is
currently restricted to use for B.C. dates related to those
recorded in the 008.  The Community Inforamtion format does not
have the 008 dates as found in the Bibliographic format, as the
004 dates -- more of them and given to the day level -- are
required for community event inforamtion.  Field 046 is not used
very much in bibliographic records because there is seldom need
to record BC dates.

Field 046 in Community Information would be defined as follows:

046   Special Coded Dates  (NR)
Indicators - Undefined
Subfield Codes
  $f    Action date  (NR)
  $g    Purge date  (NR)
  $h    Beginning date of event or program  (NR)
  $i    Ending date of event or program  (NR)

The Bibliographic format would indicate how to code 008 when this
field is used in that format, as it currently does.  In the new
variable field, the dates would not all be mandatory (even when
blank) as they were in the 004.

Change to field 004 in the Community Information format would
affect the fewest users since the format is not widely
implemented.  Community Information records including field 004
would need to be changed to prevent problems with the conflicting
definition for the field in the other formats.  Fortunately, data
in the existing field 004 would map cleanly to separate subfields
in field 046.  

Solution for field 551

In the case of field 551, the tag has been defined in the
Community Information format since its inception.  Budget
information is fairly important to programs and services which
are often described in Community Information format records.  The
conflicting field 551 was only recently defined as provisional in
the USMARC Bibliographic format.  Information gathered about the
use of this provisional field (which includes a large number of
subfields) revealed that there is not yet wide use of it in
bibliographic databases.  The Alexandria Digital Library (ADL),
which does use bibliographic field 551, reported that they have
only used subfield $o (Entity and attribute overview) and that a
change to the format would only require them to change their
ADL-to-USMARC crosswalk.  The tag of the Bibliographic field
could be changed to 552 to eliminate this conflict.  In this
case, changing the field tag in the Bibliographic format would be
the choice with least impact since the field has not been widely


The following is presented for consideration:

  -  Change field 004 to 046 in the USMARC Community
     Information format

  -  Change the name of field 046 to "Special Coded Dates" in
     both the USMARC Bibliographic and Community Information

  -  In the USMARC Community Information format, specify for
     field 046 (Special Coded Dates) undefined indicators and
     the following subfields:
      $f - Action date (NR)
      $g - Purge date (NR)
      $h - Beginning date of event or program (NR)
      $i - Ending date of event or program (NR)

  -  Change provisional field 551 to tag 552 in the USMARC
     Bibliographic format

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