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DATE: December 18, 2014

NAME: Description Conversion Information in the MARC 21 Bibliographic Format

SOURCE: Library of Congress

SUMMARY: This paper proposes defining a new field in the MARC 21 Bibliographic Format where the information regarding the process for the conversion of data in a description can be recorded.

KEYWORDS: Field 884 (BD); Description Conversion Information (BD); BIBFRAME


12/18/14 – Made available to the MARC community for discussion.

02/01/15 – Results of MARC Advisory Committee discussion: Approved, with the following amendments: 1) Also define the field in the Authority and Holdings formats. 2) Change Field Definition and Scope to read: "Used to provide information about the origin of a MARC record which has been converted by machine from another metadata structure." 3) Change subfield $k caption to "Identifier of source metadata." 4) In the subfield $k description, change "control number" to "identifier" and strike "bibliographic" from the text (new language: "Identifier associated with the description from which the data was obtained"). 5) Change subfield $d to subfield $g "Generation date" or "Conversion date", to allow space for defining possible new subfields $b - $f, should additional parsing be needed in the future.

03/23/15 - Results of MARC Steering Group review - Agreed with the MAC decision.

Proposal No. 2015-03: Description Conversion Information


As the development of BIBFRAME continues, libraries may be planning to shift part of their cataloging production to BIBFRAME in preparation of it becoming the new model for bibliographic data exchange that will ultimately replace the MARC standard.   This would most likely result in a mixed MARC/BIBFRAME environment for a number of years. In anticipation of this change, organizations are beginning to experiment with creating their original cataloging in BIBFRAME and saving their descriptions in a triple store, which will become the database of record.  Meanwhile, there will still be a need to convert the data found in BIBFRAME descriptions to MARC for loading into integrated library systems for various purposes, such as: discovery, setting holdings, links to payments, export to OCLC to support interlibrary loans and PCC obligations, etc.  As libraries work through these various MARC dependencies, they would be able to eventually eliminate them in favor of BIBFRAME.

As a result, libraries need to be able to indicate that data in a MARC record was derived and converted from a BIBFRAME description, both to let people know that there is a BIBFRAME version available that can also be accessed, and to explain any peculiarities in the MARC record itself.


There is currently no place in MARC where this type of data conversion information can be recorded.  BIBFRAME implementers have requested a dedicated MARC field that will store information about the metadata conversion process. This new field could also be used for conversions from other data descriptions, e.g. Dublin Core, MODS, etc.

In 2012, MARBI approved new field 883 (Machine-generated Metadata Provenance), which was incorporated into the MARC format, and is used to provide information about the origin of metadata in data fields in the record, with special provision for data fields that have been fully or partially machine-generated.  Field 883 has several data elements similar to those needed for description-level data conversion, such as: the process for conversion, the date of conversion, the organization doing the processing, and the URL for the process.  Field 883, however, is used for noting machine generated data in a field in the record, not the whole description/record.   It also targets generated data rather than converted data.  Therefore, a companion field would be more suitably defined to specifically address the conversion information for an entire description.

2.1. New MARC Field for Description Level Conversion Process Information

In the MARC 21 Bibliographic Format, define field 884 (Description Conversion Information) as a companion field to field 883 (Machine-generated Metadata Provenance), using similar data elements that address the conversion at the description level:

884 – Description Conversion Information (R)

Field Definition and Scope:

Used to provide information about the origin and conversion of an entire description. Intended for use when the data in the MARC record have been fully or partially converted by machine from another metadata structure.

First Indicator
# - Undefined

Second Indicator
# - Undefined

$a – Conversion process
Identifies the process used to produce the data contained in the MARC record. The subfield may contain a process name or some other description.

$d - Conversion date
Date on which the data was converted. Date is recorded in the format yyyymmdd in accordance with ISO 8601, Representation of Dates and Times.

$k – Identifier of origin description
Control number associated with the bibliographic description from which the data was obtained.

$q - Conversion agency
MARC organization code of the institution using the process/activity to convert the data.
Code from: MARC Code List for Organizations.

$u - Uniform Resource Identifier
Uniform Resource Identifier (URI), for example a URL or URN, which identifies the process used to convert the data contained in the MARC record. The URI can lead to a textual or structured description of the process, or the URL that was used to generate the record’s content can be provided directly, i.e., a URL invoking a web service or conveying an API call.


2 examples of BIBFRAME to MARC conversions:

884 ## $a Bibframe to MARC transformation, version 1.011
$d 20140910 $k  $q DLC

884 ## $a Stanford Bibframe to MARC transformation, version 1 $d 20141002 $k stfbf1039806 $q CSt $u

2 examples of MODS to MARC conversions:

884 ## $a MODS 3.4 to MARC LC standard transformation $d 20140910 $k $q DLC

884 ## $a Custom MODS to MARC transformation for project A  $d 20141208  $k druid:ab123cd4567  $q CSt  $u


This proposal is about a MARC field for recording the process used to transform data from BF to MARC and that would not be relevant to BIBFRAME.  However, there are fields in the admin section of the BF vocabulary that indicate the MARC, MODS, OCLC, or other record that is the source of information in the BIBFRAME description:  bf:derivedFrom, bf:generationProcess (the process used to make the conversion), and bf:generationDate.


In the MARC 21 Bibliographic Format, define new field 884 (Description Conversion Information) as described above.

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