AN ANALYSIS OF THE USE OF MODS IN DIGITAL REPOSITORIES

By Carrie Moran

PROJECT GOAL

To examine the Metadata Object Description Schema (MODS) metadata scheme to determine its utility based on structure, interoperability and metadata quality.

MODS <HISTORY>

Developed by the Library of Congress’ Network Development and MARC Standards Office (Guenther, 2010)

Purpose: to provide a schema and guidelines for encoding a resource description

MODS <GOALS>

Goals

Support localization and customization needs Accommodate widely adopted descriptive practices Maintain a relatively small number of elements and attributes to reduce training, application, and implementation costs Support the communication of resource and authority descriptions Support validation of the encoding Allow use of MODS/MADS elements by other standards and in application profiles Maintain continuity of structure and content Maintain a single way to encode a piece of information Accommodate indexing of data in the description Accommodate presentation of data in the description Make element and attribute names as intelligible as possible to a general audience Allow for extensibility to include data from richer element sets Accommodate information about the metadata and record itself Accommodate conversion to and from other commonly used resource and authority description encodings (such as Dublin Core,

MARC, VRA Core) Accommodate controlled vocabularies that are commonly used in resource and authority description Allow full description of whole-to-part and similar types of relationships Support encoding a description for any type of resource Support encoding the relationship of an agent to a resource

(from http://www.loc.gov/standards/mods/design-principles-mods-mads.html)

MODS <COMMUNITY>

Implementation Registry: projects using MODS that are in planning, in progress, and completed

There are currently 34 projects in the Implementation Registry

MODS is currently being used for a variety of purposes and formats

Example: used by UC Berkeley for Computer Science Technical Reports; Archival, Rare and Fragile Collections; and Digitized Tables of Content

MODS <STRUCTURE>

Expressed in XML format Composed of 20 top level elements and 56

sub-elements Each element can be combined with attributes

to allow for more precise records Each element can be used multiple times

throughout a single record, with the exception of <recordInfo>

There are no mandatory or standard elements Elements can be presented in any order

MODS <ELEMENTS>

Top Level Elements: <abstract> <accessCondition> <classification> <extension> <genre> <identifier> <language> <location> <name> <note> <originInfo> <part> <physicalDescription> <recordInfo> <relatedItem> <subject> <tableOfContents> <targetAudience> <titleInfo> <typeOfResource>

MODS <EXAMPLE RECORD><mods version="3.3" ><titleInfo>

<title>Learning XML [electronic resource]</title></titleInfo><name type="personal">

<namePart>Ray, Erik T.</namePart></name><typeOfResource>text</typeOfResource><originInfo>

<place><placeTerm type="text">Beijing</placeTerm>

</place><place>

<placeTerm type="text">Cambridge, Mass.</placeTerm></place><publisher>O'Reilly</publisher><dateIssued>2001</dateIssued>

</originInfo><language>

<languageTerm authority="iso639-2b" type="code">eng</languageTerm></language><physicalDescription>

<form authority="marccategory">electronic resource</form><extent>1 online resource (xii, 354 p.): ill.</extent>

</physicalDescription><note type="statement of responsibility">Erik T. Ray</note><note type="source of description note">Description based on print version record.</note><subject authority="lcsh">

<topic>XML (Document markup language)</topic></subject><identifier type="uri">http://proquest.safaribooksonline.com/0596000464</identifier><recordInfo>

<recordCreationDate>2011-04-14</recordCreationDate></recordInfo></mods>

MODS <GUIDELINES>

MODS Guidance Page contains links to MODS User Guidelines MODS Note Types Sample MODS Version 3 XML Documents MARC Code Lists Available as Linked Data Sources Value lists(

http://www.loc.gov/standards/mods/mods-guidance.html)

MODS <GUIDELINES>

MODS User Guidelines (Version 3) available at http://www.loc.gov/standards/mods/userguide/

Contents:

Introduction and Implementation -XML Structures-Implementation Notes

MODS Elements and Attributes -Top Level Elements in MODS-Attributes Used Throughout the MODS Schema

MODS "Lite"MODS Full Record ExamplesAlphabetical Index of MODS Elements by Element Name

MODS <GUIDELINES>

Each top level element has its own page listing its definition, attributes, and sub elements

The top level elements pages also provide guidelines, a description, examples, and mappings

Extensive guidelines enhance metadata creators’ ability to create complete, accurate, and consistent records

MODS <CONVERSIONS>

One of the goals of MODS is “Accommodate conversion to and from other commonly used resource and authority description encodings”

This goal is achieved through the provision of mappings, stylesheets, and conversion tools

MODS Website Conversions page links to websites, Excel files, and XML files for the following schemes: MARC, RDA, Dublin Core, and MARCXML

http://www.loc.gov/standards/mods/mods-conversions.html

MODS <METS>

The Metadata Encoding &Transmission Standard (METS) was also developed by the Library of Congress

METS is “a standard for encoding descriptive, administrative, and structural metadata regarding objects within a digital library” (Library of Congress)

METS was designed to facilitate the management and exchange of digital objects across repositories

MODS is frequently used within the Descriptive Metadata section of a METS record

The nesting of MODS information within a METS record serves to enhance the interoperability of MODS records across repositories

CONTROLLED VOCABULARIES

MODS scheme allows for the use of any controlled vocabulary

Controlled vocabularies work to enhance specificity of item records and to enhance interoperability between records using the same vocabularies

The “authority” attribute can be used with six of the top level elements to designate which controlled vocabulary is being used for that particular element.

Example: <subject authority=“lcsh”>

<topic>History</topic> <geographic>United States</geographic>

<subject>

ANALYSIS

To test the effectiveness of MODS in a real world setting, three repositories were chosen from the MODS Implementation Registry

Repositories were chosen based on the availability of MODS records for public view.

Twenty-five records from each repository were analyzed for controlled vocabulary usage, completeness, accuracy, and consistency.

REPOSITORIES

Copac http://copac.ac.uk/ Catalog containing records from 71 libraries No guidelines for metadata usage provided on their websiteUniversity of Florida Digital Collections http://ufdc.ufl.edu/ Over 300 distinct digital collections All metadata built using SobekCM open source software Website contains extensive guidelines for the use of MODS and METS in

their collectionsLibrary of Congress Web Archives http://lcweb2.loc.gov/diglib/lcwa/html/lcwa-home.html 15 collections of archived websites Website provides a short but detailed Technical Information page

outlining metadata usage and application

COPAC <CONTROLLED VOCABULARY USAGE>

80% of records used MARC Genre Term list for <genre> element

12% of records used the <subject> element, of these, 2 used Library of Congress Subject Headings (LCSH) and 1 used uncontrolled vocabulary terms

When controlled vocabularies were used, they were implemented properly

COPAC <METADATA QUALITY>

5 of 20 top level elements were used in every sample record

5 of 20 top level elements were not used in any sample records

Many elements used only in records to which they apply, ex. <language> used for written materials but not photographs

Only 12% of sample records made use of the <subject> element, this is problematic because subject searching is often a first step in the search process

None of the records used the <typeOfResource> which means that users cannot sort or browse by type

UFDC <CONTROLLED VOCABULARY USAGE>

72% of sample records used the<subject> element, and each of these elements used LCSH

8% of records used MARC Genre Term list for <genre> element

When controlled vocabularies were used, they were implemented properly

A majority of records using the <subject> element used the same exact terms

This makes it difficult to distinguish between collection items based on subject alone

UFDC <METADATA QUALITY>

3 of 20 top level elements were used in every sample record

6 of 20 top level elements were used in no sample records

Of the remaining top level elements, 5 were used in a majority of records

As mentioned previously, much of the inconsistency in usage can be attributed to the fact that not all elements apply to every record

UFDC sample records made extensive use of sub-elements and attributes

LOC <CONTROLLED VOCABULARY USAGE> 100% of sample records used the <subject>

element with LCSH subject terms Many of the records also used the Thesaurus

of Graphic Materials (TGM) and uncontrolled subject terms

Several records used the LCSH Name Authority File for the <name> element

The use of controlled vocabulary terms was implemented correctly in all records examined

LOC <METADATA QUALITY>

14 of 20 top level elements were used in every sample record

4 of 20 top level elements were not used in any sample records

<name> and <targetAudience> were the only top level elements used in only some records

<targetAudience> is not frequently determined on websites, and is an element that is likely to only be used for certain items

The inconsistent use of the <name> element (only in 5 records) is troubling because one would expect some type of personal or corporate name to be associated with a majority of websites

COMPARISON

All three collections contained metadata of relatively good quality

Elements were applied accurately and consistently throughout the collections.

The LOC repository is clearly the most complete and consistent, the limited scope of the collections combined with the fact that the LOC developed both the MODS scheme and the repository is the likely cause of this completeness

The UFDC and Copac repositories both lack completeness and consistency, however, the UFDC’s use of sub-elements and attributes gives it an edge over Copac

The UFDC and Copac collections contain a much wider variety of materials, which is evident in their application of metadata

CONCLUSION

Each repository examined used the MODS scheme correctly and consistently across sample records

This speaks to the effectiveness of the MODS scheme and the availability of guidelines and mapping information

The MODS element set is designed to enhance quality while allowing for flexibility.

The MODS guidelines are thorough, and the amount of elements, sub elements and attributes works to limit any semantic challenges in application of elements.

This examination has shown MODS to be a well-structured, interoperable scheme that can be used to create high quality metadata records

REFERENCES

Guenther, R.S. (2003). MODS: The Metadata Object Description Schema. Libraries and the Academy, 3(1),137-150.

Library of Congress. (2009). Design Principles for Enhancements to MODS and MADS. Retrieved from http://www.loc.gov/standards/mods/design-principles-mods-mads.html

Library of Congress. (2011). Metadata Encoding and Transmission Standard. Retrieved from http://www.loc.gov/standards/mets/

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Signature Carrie E. Moran Date       May 28, 2011