MODS: Metadata Object Description Schema

Executive Summary As digital library projects have expanded in number, the need for standardization of their metadata has become more acute. A standard framework for this metadata is now provided by METS (Metadata Encoding and Transmission Standard), but its usefulness is limited by the lack of a satisfactory standard for metadata content. In the area of descriptive metadata, the key initiative until now has been Dublin Core: it has been hampered, however, by the conflicting needs of interoperability and precision which it has failed to resolve. MODS (Metadata Object Description Schema), a new standard published by the Library of Congress' Network Development and MARC Standards Office, aims to allow reconcile these demands in a single, coherent scheme for describing digital objects. MODS, written in XML, provides 19-top level elements for describing objects, and a further 64 sub-elements under these. These cover standard bibliographic facets such as titles, names of creators and contributors, subject and classification numbers, and also such areas as physical description, information on access restrictions, and genre. It also includes mechanisms for extending its element set by incorporating other XML documents within its structure, and allows records for related objects to be incorporated in this way. In addition, it includes facilities for authority control, and is fully granular in the level of descriptions it provides. MODS has arrived at a time when the current heterogeneity of approaches to metadata is becoming untenable: it reconciles the problems Dublin Core has experienced by providing a richer element set but still allowing extensibility when required. As it is an XML application, it is non-proprietary and not tied to any given software package. Tools have already been written to convert MARCXML records to MODS and further similar tools are easily written. MODS has already been used for a wide variety of classes of material, from books to multi-media, and has been adopted by a number of major digital library projects. Its use is also being widely promoted by key bodies in the digital library world. When used in conjunction with other key standards, such as METS, it offers the potential for a fully coherent, integrated metadata strategy which will much enhance access to digital materials worldwide. However, until a critical mass of MODS records is created, the full advantages of its adoption, in terms of facilitating the creation of collections which can easily interact with each other, will not be obvious: its …