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DATE: May 30, 2007
NAME: Use of field 520 for content advice statements in the MARC 21 bibliographic format
SOURCE: Revealweb Union Catalogue
SUMMARY: This paper proposes using field 520 (Summary, etc.) in the bibliographic format to carry advice statements about types of content in items, primarily but not solely, for visually impaired users. It also proposes defining subfield $c to identify the agency that supplied the advice and subfield $2 for the source code of the classification system used. It also proposes adding a new first indicator value to signify content advice information.
KEYWORDS: Field 520 (BD), Subfield $c, in field 520 (BD), Subfield $2, in field 520 (BD), Content advice (BD), Content warning (BD)
RELATED: 2006-DP02 (January 2006); 2007-DP02 (January 2007)
05/30/2007 - Made available to the MARC 21 community for discussion.
06/23/2007 - Results of the MARC Advisory Committee discussion - Approved as amended. The name of subfield $c will be generalized to include entities such as journals and newspapers.
07/13/2007 - Results of LC/LAC/BL review - Approved
A recent initiative in the UK set out to provide a web-based union catalog of materials available in accessible formats in the UK. Launched in 2003, the Revealweb Union Catalogue uses MARC 21 bibliographic and holdings formats. In order to provide the level of detail required for users, it proved necessary to display content advice statements in some bibliographic records.
Discussion Paper 2006-DP02 (Addition of coded value to 008 for content alerts in the MARC 21 bibliographic format) proposed adding a coded value to field 008/32 in the bibliographic format to enable this information to be used as a search filter. Concern was expressed over re-using an obsolete 008 position and the MARC Advisory Committee decided against making the proposed extension to 008 coding.
However, the principle of the need for this information in bibliographic records was accepted and it was suggested that a new discussion paper be submitted for using a variable field to hold content advice statements.
Discussion Paper 2007-DP02 (Use of field 520 for content advice statements) discussed coding either field 520 (Summary, etc.) or 521 (Target Audience Note) in the bibliographic format to carry advice statements about types of content in items. A slight majority of the MARC Advisory Committee favored using bibliographic field 520 for content advice statements, rather than field 521, which is more of a value judgment. It also agreed to define both subfield $c to identify the agency that supplied the content advice statement and subfield $2 to identify the content advice classification system used. Adding a new first indicator value signifying content advice information was also recommended by the MARC Advisory Committee.
Within the Revealweb Union Catalogue, content advice statements are held in field 520 (Summary, etc.). Although Revealweb currently uses the first indicator position value 2 (Scope and content), a new first indicator value may be needed if content advice statements are to be assigned more widely in the future by different agencies.
The first indicator values currently defined for bibliographic field 520 are:
520 - Summary, etc.
First indicator: Display constant controller
# = Summary
0 = Subject
1 = Review
2 = Scope and content (currently used for Revealweb content warnings)
3 = Abstract
8 = No display constant required
It is proposed that value 4 be added to the first indicator position for content advice information.
2.2 - Definition of subfield $c as Assigning agency for field 520
Subfield $c (Assigning agency) may be added to field 520 to contain an organization code or the free text name of the agency that supplied the data (summary, review, abstract, content advice statement, etc.) coded in subfield $a. For example, the organization code for the public library that assigned a content advice statement to a popular movie would be recorded in subfield $c of field 520. Although it is expected that subfield $c is most relevant to content advice statements, it could apply to other instances of the field specified by other indicator values, e.g. the organization that supplied an abstract. It is not necessary to provide separate subfields for coded vs. textual forms of the organization's name; note that in field 852$a either a code or free text may be used to record the holding institution.
2.3 - Definition of subfield $2 as Source for field 520
Subfield $2 (Source) may be added to field 520 to contain the source code for the particular classification system used to construct the content advice statement recorded in subfield $a. For example, the MPAA (USA) and BBFC (UK) film classification systems are used frequently for content advice information and use of these classification schemes may be coded in subfield $2. It is likely that this subfield would apply only to 520 fields coded in the first indicator as value 4, since the content of the field specified by the other values do not lend themselves to controlled values taken from a specific source.
520 4# $aContains violence$c[Revealweb organization code]
520 4# $aContains swear words, sex scenes and violence$c[Revealweb organization code]
520 4# $aContains strong sexual theme and fetish scenes$cCentral County Library $2[Source code for the content advice classification system used]
520 4# $aContains crude humour$c[Assigning agency's organization code]$2[Source code for the content advice classification system used]
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