Guidelines for using Agent Roles in Dublin Core (Draft) 1/23/04, dih 2/12/04, rsg 2/16/04, dih 2/23/04, tb (converted to plain text only) Function of roles and history of approval by DCMI The need to express a role for the "Agent" elements (Creator, Contributor, and, to a lesser extent, Publisher) in the Dublin Core element Set has been expressed for many years and there have been a number of ideas for how to handle this. A role is a term that further refines the contribution of the agent to the resource described; an example is "illustrator" might be a role associated with the element Contributor when that person provided, for example, illustrations to the resource rather than being entirely responsible for all aspects of the intellectual content. The DCMI Usage Board has discussed the issue several times and agreed that the role values are properly element refinements. At its meeting in Florence in Oct. 2002, the Board generally agreed that deprecating Creator and Publisher in favor of Contributor should be considered, since the role values Creator and Publisher could be used to refine Contributor if needed. Because of negative response to this sort of change in the Dublin Core element set, the DCMI Usage Board decided to recommend role refinements only to Contributor, but to leave Creator, Contributor and Publisher as separate elements. Because a standardized, widely adopted list of roles already existed in the MARC Code List for Relators, it was recommended early in these discussions that DCMI not develop its own. In early 2000 a subset of the MARC relators list was circulated for approval to include 10 generally applicable roles out of the approximately 150 MARC relator terms. Because of the need to consider other aspects of the "Agent" issue, at that time the proposal was deferred. Discussion initially in the DC-Libraries Working Group (which prepared an application profile for use in libraries that included the relator terms) and later in the DCMI Usage Board revealed that consensus was that users not be constrained by a small list of elements and that the entire list of relator terms should be available given the difficulty of anticipating needs in various domains. The Library of Congress has prepared an RDF expression of the MARC relator list, to be used in conjunction with the Dublin Core element Contributor. This is available at: http://www.loc.gov/marc/dc/marcrelcodes.rdf (note: this is not yet a persistent URI but Rebecca will provide one!). The MARC Relator list, what it is and how it's structured The MARC Code List for Relators was developed for use in MARC 21 bibliographic records to express the relationship between a name and a work. The list includes both role terms and three-character codes that represent those terms. The terms were only included on the list if the name and its associated role were considered important enough to include on a bibliographic record as a contributor. Thus, all terms represent possible contributions to a resource. The Library of Congress is the maintenance agency for this list and regularly adds new ones when the need is expressed and documented. The MARC Relator list includes three-character alphabetic codes to be used to identify roles. These are to be considered synonyms for the term they represent. In addition the list provides definitions for use of the term/code. In the RDF representation, the codes are tokens to be used for the term and are part of the URI. In some cases unused terms refer to used terms; these are included in the RDF representation as a note (dc:description). All terms are declared as refinements of dc:contributor. Using Roles with Contributor In order to minimize the possibility of confusion, the Usage Board has authorized the use of roles only with the element Contributor. Because Creator is in some sense a role elevated to a position at the level of element, the Board's position is that it makes no sense to provide yet another level of roles beneath that particular element. Because Publisher and Creator each appears on the list of MARC Relator terms, and the entire list is available to be used as roles, it is acceptable to use the role of Publisher or Creator instead of the element within an implementation. If marc:creator is used instead of dc:creator, the two terms should probably not be used together in the same instance. Because roles are to be used only with the Contributor element, appropriate "Dumb Down" of all agent refinements expressed as roles will be to Contributor. Given this, implementations may choose (preferably within the context of an application profile), to specify explicitly whether the MARC relator terms of publisher or creator may be used, based on the fact that the distinction could be retained in Simple Dublin Core if the Element level term is retained for those particular roles. Using Roles in XML and other Schemas Because the maintenance of the MARC Relator list will remain with the Library of Congress, the namespace of the roles will be established by LC and will not be a DCMI namespace. Thus, schemas will need to include the MARC relator namespace in order to properly express role terms. See the document Guidelines for Implementing Dublin Core in XML for specific information on using non-DCMI namespaces. Terms not on the MARC Relators list The MARC Relator list has been developed over many years to meet a wide variety of needs. New terms are added on the basis of need, and LC has expressed willingness to continue to expand the list upon request. Implementers also have the option to create and expose alternative vocabularies for the expression of other kinds of roles not reflected in the MARC Relator list. Managing the Use of Role in an Implementation The MARC Relator list is large, including approximately 150 separate terms for various roles. Some of the roles on the list were created for specific domains, and would be of little use in other communities. It might therefore be useful for implementations to declare a subset of the role vocabulary as relevant to their specific goals, preferably by way of a formal application profile.