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Metadata Formats

metadata component for METS-generated records. Likewise, the MODS
schema was tapped as one of the registered metadata formats for SRU/SRW,
the next-generation communication format designed as a replacement for
Z39.50. So, while MODS was created to work as a stand-alone metadata
format that could be used for original record creation, translating MARC
data into XML, and facilitating the harvesting of library materials, it was
also created as part of a larger ongoing strategy at the Library of Congress
to create a set of more diverse, lightweight XML formats that would have
the ability to work with the library community’s current legacy data.

Strengths
As mentioned earlier in the chapter, MODS has a number of advantages
over other general-purpose metadata schemas like Dublin Core when
one considers the current environment within the library community.
While applications like digital repositories tend to avoid using MARC for
bibliographic description, the reality is that MARC still dominates the
metadata landscape within the library community. Nearly all major ILS
vendors currently support MARC as their de facto metadata schema, lead-
ing to thousands of MARC-filled databases. The ability of MODS to provide
an element set that is already compatible with the existing bibliographic
descriptions within these large MARC databases provides a clear migration
path for users to an XML-based schema. This is very different from other
schemas like Dublin Core, which lacks the granularity of elements needed to
provide a clear migration path away from something like MARC. By providing
this compatibility, MODS can provide a bridge as the metadata continues to
evolve. This increased granularity also allows MODS records to provide richer
descriptions than those found within a Dublin Core record. MODS utilizes
an expanded element set (about twenty high-level elements, coupled with
multiple refinements) to encourage richer bibliographic description, and as
a result, it is well-suited for the hierarchical nature of the METS framework.
MODS introduces the ability to utilize hierarchies within the biblio-
graphic description of an item. This is very different from MARC and even
Dublin Core, which are flat metadata schemas, meaning that their descrip-
tions are limited to the item that they are describing. MODS provides the
capability for users to describe an idea, as well as the parts that make up
that item, arranging the bibliographic description hierarchically within the
record. This allows MODS objects to create “actions” around the various
levels of the hierarchy, and it encourages software designers to utilize these
hierarchical elements in displaying relationships within, to, and from an
individual resource.

Challenges
Like Dublin Core, MODS’s biggest challenge is a result of its biggest asset.
While MODS does not prescribe any set of input rules upon the metadata
framework, its close relationship to MARC emphasizes the type of data that is
best suited for this format. The Library of Congress has attempted to position
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