The Use of MODS in Digital Repositories

1. The Use of MODS in Digital Repositories Cathleen Lu INFO 662 FALL 2010 Kilzer

2. Introduction Digital repositories employ metadata for content description and discovery Metadata schemes, such as MODS, are structured element sets for describing information Standardized schemes are important for interoperability in the sharing of resources

3. Metadata Object Description Schema (MODS) • Derived from MARC 21, MODS was developed by the Library of Congress Network Development and MARC Standards Office • Comprised of twenty top-level elements • “No element is mandatory in a MODS record, however, every MODS record requires at least one element” (Library of Congress, 2010) • With the exception ofrecordInfo, all elements are also repeatable (Library of Congress, 2010)

4. More on MODS The twenty top-level elements are:

5. Metadata Evaluation Project • This project examines two digital repositories implementing MODS in their: • Use of metadata elements • Metadata quality and consistency • Use of controlled vocabulary • Documentation and guidelines • Semantic interoperability

6. Project Methods Thirty records were examined from each repository for a total of sixty records Local element descriptors were mapped to MODS element fields Frequency of element use was tallied Metadata was evaluated for completeness, consistency, accuracy, comprehensibility, and overall quality

7. Digital Repositories The Library of Congress Performing Arts Encyclopedia (PAE) is a guide to performing arts materials in the Library’s collection—[http://www.loc.gov/performingarts/] Music Australia is a resource on Australian music developed by the National Library of Australia, the National Film and Sound Archive, and other cultural institutions across Australia—[http://www.musicaustralia.org/]

8. Metadata Mapping and Usage for PAE

9. Metadata Mapping and Usage for Music Australia Fields marked with * denote best guess of mapped element due to ambiguity

10. Usage and Frequency of MODS Elements • The PAE implemented ten top-level elements in the records examined, with nine at 100% usage • Elements in bold are ones expressed in all records: titleInfo, originInfo, language, physicalDescription, abstract, note, subject, classification, location, recordInfo • While the recordInfo field is not displayed in the bibliographic record, it is present in the XML layout

11. Usage and Frequency of MODS Elements • Music Australia used thirteen top-level elements in the records examined, and ten of the fields are at 86% usage or above • Bolded elements are the most frequent: titleInfo, originInfo, name, relatedItem, physicalDescription, abstract, note, subject, identifier, accessCondition, language, location, recordInfo • While typeOfResource is listed as a required value in the documentation, it was not displayed in the item record and there was no way other way to verify use of the element

12. Metadata Quality and Consistency • The Performing Arts Encyclopedia: • Records are excellent throughout, andpunctuation and formatting of metadata are error free • The only identifiable errors and inconsistencies are with minor capitalization issues • All subjects and URLs are linked correctly, allowing for browsability to related records and collections

13. Metadata Quality and Consistency • Music Australia: • Records are error free, but highly varying descriptors for repeating MODS elements contributes to inconsistency and ambiguity • Some MODS elements are used interchangeably • Metadata formatting is more MARC oriented • URLs are linked correctly but not labeled clearly

14. Controlled Vocabulary Use • Controlled vocabulary use for the PAE varies with record type • Vocabulary schemes include Library of Congress Authorities and Subject Headings, the Thesaurus for Graphic Materials, and other subject authorities not listed in MODS source codes • Subject/genre fields in Music Australia follow LCSH formatting, but personal names do not use LC Authority Records

15. Documentation and Guidelines • The PAE has no online documentation of local metadata creation guidelines on its website, though “Display XML” links are available for all records in the repository • Music Australia provides metadata guidelines for contributors, which, while helpful, do not correspond thoroughly with its records • Precise fields are not specified and certain MODS elements are allowed to be used interchangeably

16. Barriers to Interoperability Inconsistent use of controlled vocabularies in the PAE Large array of local fields combined with lack of clarity in use in Music Australia creates confusion Interchangeable abstract/note and identifier/location fields in Music Australia contributes to inconsistency and ambiguity

17. Conclusion MODS allows description from existing MARC records or from the creation of original resources Both repositories use a select set of MODS elements but support extra fields for additional information Inconsistency and ambiguity are the major issues with metadata and are problematic for interoperability Clearly defined local guidelines and adherence to controlled vocabularies can improve both metadata quality and interoperability