PROPOSAL NO.: 2002-03

DATE: December 18, 2001
REVISED:

NAME: Expanding Field 046 for Other Dates in the MARC 21 Bibliographic Format

SOURCE: Library of Congress; CORC

SUMMARY: This paper proposes defining new subfields for date modified, date created, beginning date valid and ending date valid in field 046 to provide a place for dates that do not fit into other data elements currently defined in the MARC 21 bibliographic and community information formats.

KEYWORDS: Created dates (BD); Dates (BD); Field 046 (BD); Modified dates (BD); Valid dates (BD); Special coded dates (BD)

RELATED: 98-04 (January 1998); 98-07 (June 1998); 2001-DP03 (January 2001); 2001-DP04 (May 2001)

STATUS/COMMENTS:

12/18/01 - Made available to the MARC 21 community for discussion.

01/21/02 - Results of the MARC Advisory Committee discussion - Approved as amended. Participants agreed that "Date created" may be expressed as a date range and thus, subfield $k should be defined as "Beginning or single date created" and subfield $l should be defined as "Ending date created." Participants also felt that subfield $j should be renamed as "Date resource modified" to more accurately reflect the types of dates it will contain.

03/20/02 - Results of LC/NLC review - Agreed with the MARBI decisions.


PROPOSAL NO. 2002-03: Expanding Field 046 for Other Dates

1. BACKGROUND

There are numerous dates associated with bibliographic items that are included in different fields of the MARC bibliographic and community information formats. For example, in the bibliographic format, field 260 (Date of publication, distribution, etc.) is for the publication date and field 005 (Date and Time of Latest Transaction) is for the date and time of the latest transaction. Although the formats contain many dates, the question arises as to whether others are needed for new types of materials, especially for electronic resources.

In January 2001, the MARC Advisory Committee discussed Discussion Paper 2001-DP03 (Types of Dates for Electronic Resources in MARC 21 Formats). The paper originally dealt with dates needed for the Dublin Core element set qualifiers. The group decided that a new discussion paper should be presented that more generally explored the issue about different types of dates that are currently not in the MARC 21 formats. Two were specifically identified: the date that a resource had been modified and the date that a resource was valid.

In June 2001, the MARC Advisory Committee discussed Discussion Paper 2001-DP04 (Expanding Field 046 for Other Dates in the MARC 21 Bibliographic and Community Information Formats). The group agreed that field 046 could be used for other dates that do not fit into existing fields in the MARC 21 formats. For non-publication dates, separate subfields could be used. Four dates were identified as possible candidates for field 046 during this discussion: date modified, date created, beginning date valid and ending date valid. Participants also suggested that subfield $2 (Source) be defined in field 046 to allow for the use of different types of date schemes in the field. Although field 046 is currently non-repeatable, the group recommended that it should be made repeatable to specify each form of date used in the field.

Field 046 (Special coded dates) is defined in the MARC 21 bibliographic format to contain date information that cannot be recorded in field 008/06-14. It was recently expanded in Proposal No. 98-07 to include not only B.C. dates, but also incorrect publication dates, a need requested by the rare book community. It could be expanded further to include other types of dates, although now it is primarily used for dates of publication. Currently, the following subfields are defined:

$a - Type of date code (NR)
$b - Date 1 (B.C. date) (NR)
$c - Date 1 (C.E. date) (NR)
$d - Date 2 (B.C. date) (NR)
$e - Date 2 (C.E. date) (NR)
$6 - Linkage (NR)
$8 -Field link and sequence number (R)

Field 046 is also available in the community information format, where it is used for coded date information that is potentially useful for retrieval and data management purposes for community information resource records. This information had previously been recorded in field 004, but was changed to field 046 in an effort to resolve discrepancies in the bibliographic and community information formats for the SGML/MARC DTD that combined these formats. (See Proposal No. 98-04: ). The following subfields are currently defined:

$f - Action date (NR)
$g - Purge date (NR)
$h - Beginning date of event or program (NR)
$i - Ending date of event or program (NR)
$8 - Field link and sequence number (R)

In the MARC Advisory Committee discussion of 2001-DP04, consensus emerged that the bibliographic and community information fields should not be merged. Any definition of new subfields in the bibliographic 046 field should not reuse those defined in the community information format.

2. DISCUSSION

2.1 Definition of Subfield $j for Date Modified

Date modified describes a date in which a resource has been changed or updated, but does not constitute a new work. In some cases, the date modified may be the only date provided. It may also be recorded to the hour. Although date modified would not be used for some continuing resources, such as serials, it should be used for integrating resources, such as websites and other electronic media. It would be inappropriate, however, to code date modified for loose-leafs because many libraries currently use either their check-in systems or a holdings field to keep track of the latest date of updates filed into loose-leaf materials.

Date modified may be an important element to record in MARC records to allow for accurate and up-to-date resource discovery of Web pages in library catalogs. Defining a data element for date modified may also help map the formats to other metadata standards. Unfortunately, the practice of recording date modified is very laborious and prone to errors. Likewise, it may be misleading for in most cases, only the top level pages on Web sites are cataloged and thus, this date may exclude all of the modified dates in the content-rich lower level pages.

Subfield $j could be defined as:

$j - Date modified
Subfield $j contains the date on which a resource has been changed or updated. Dates in subfield $j usually relate to Web pages and other electronic media that routinely contain the date of last update.

046 ## $j20010712
245 00 $aCounty business patterns, United States.
856 41 $uhttp://www.census.gov/prod/www/abs/cbptotal.html$zScroll down to "United States" and click on desired issue
[The item was last modified on July 12, 2001]
 
046 ## $j199908
245 00 $aGuidelines for the Use of Field 856
856 40 $uhttp://www.loc.gov/marc/856guide.html
[The item was last modified in August, 1999]

2.2 Definition of Subfield $k for Date Created

Date created is a primary date used for resource discovery. Currently, there is no one place coded in the MARC 21 formats for creation date since it implies several different meanings. Places in the format for date created include the date in a uniform title (field 130 or 240), date of the reproduction (field 533), and the date of the original (field 534). Because Web and other electronic resources contain somewhat ambiguous dates of creation that do not fall within traditional cataloging guidelines, it may be advantageous to provide clearer guidance on how to code for their creation dates in the formats. Defining a data element for creation date not recorded elsewhere could also help map the formats to other metadata standards with greater success.

Subfield $k could be defined as:

$k - Date created
Subfield $k contains the date on which a resource has been created when it is not more appropriately recorded in another field. Dates contained in subfield $k may not be coded elsewhere in the formats.

046 ## $k19981022
245 00 $aMARC 21: Harmonized USMARC and CAN/MARC
856 40 $uhttp://www.loc.gov/marc/annmarc21.html
    [The item was created on October 22, 1998]

2.3 Definition of Subfields $m and $n for Date Valid

Date valid is the date that the content of a resource is valid and is often expressed as a range of dates. Because many Web sites and other electronic resources contain date-sensitive information, date valid elements could be very useful to record for resource management activities. Unfortunately, providing date valid data could be very laborious to keep current because of the fluid nature of information on the web.

Subfields $m and $n could be defined in as:

$m - Beginning of date valid
Subfield $m contains the beginning of the date span for the validity of a resource.

$n - End of date valid
Subfield $n contains the ending of the date span for the validity of a resource.

046 ## $m20011008$n20011027
245 00 $a<Title of train schedule>
856 41 $u<URL to train schedule>
    [The train schedule is valid from October 8, 2001 - October 27, 2001]

2.4 Definition of Subfield $2

Because different date schemes may be used in field 046, subfield $2 (Source of date) could be defined to indicate the source of date scheme used in the field. The subfield would be used when a form different than the ISO 8601 form used in many MARC fields (such as field 005) is recorded.

Subfield $2 could be defined as:

$2 - Source of date
Subfield $2 contains a code that identifies the source of the date scheme used in the field. The source of the code is the MARC Code Lists for Relators, Sources, Description Conventions, that is maintained by the Library of Congress. [A list of codes would be developed.]

046 ## $j2001-07-12$2<Code for W3CDTF>
245 00 $aCounty business patterns, United States.
856 41 $uhttp://www.census.gov/prod/www/abs/cbptotal.html$zScroll down to "United States" and click on desired issue
    [Note that W3C DTF is an alternative form specified in ISO 8601]

2.5 Repeatability of Field 046

Because dates can be recorded in many different forms (for example, ISO 8601, International standard for the representation of dates and times, describes two types of date/time formats), it is important that they are recorded in predictable ways to accurately interpret them. Currently field 046 is non-repeatable, however, it could be made repeatable to record different types of date formats used in the field. Repeating field 046 could provide both flexibility in the kinds of dates used and allow metadata standards to be mapped to the MARC 21 formats with greater ease. If subfield $2 is different, the field is repeated.

3. PROPOSED CHANGES

In field 046 (Special Coded Dates) of the MARC 21 Bibliographic and Community Information Formats:


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