Social Tagging, Library of Congress’ Subject Headings, and Library Catalogs

Social Tagging, Library of Congress’ Subject Headings, and Library Catalogs

by

Jason W. Dean

IST 616

Syracuse University

Social Tagging, Library of Congress’ Subject Headings, and Library Catalogs, 2

Over the past several years the explosion of information associated with the

digitization of information resources has led to the creation of systems for user-created

tags, also known as collaborative tags. These systems allow users of electronic

information resources to assign tags, of relevance to the user, to the information object

itself. These tags, however, are separate from the traditional form of “tagging” in the

library catalog, specifically the Library of Congress Subject Headings. These headings,

alternatively referred to as Library of Congress Authorities, and referred to as LCSH in

this paper, are a massive collection of controlled vocabulary words used for the

description of subjects, organization, places, and individuals in library catalog records.

Both social tags and LCSH provide useful and helpful access points for catalog users.

Furthermore, both systems offer strengths and weaknesses, which are complimentary to

one another. This paper looks briefly at each system and the proposed methods by which

social tags and the LCSH can be integrated in a way that will help the user to find the

information resources they seek.

As pointed out in the Macgregor (2006) article, controlled vocabularies perform

many useful functions, including:

• Managing synonyms and other easily confused terms – This prevents the

description of one “thing” by many terms. For example, without a controlled

vocabulary, items about George W. Bush and George H. W. Bush might both be

described through the term “George Bush.” A controlled vocabulary ensures that

the terms are unique, as well as consistent, across catalogs thereby increasing the

ease of searching for users.

• Discriminates between homonyms – This function eliminates the confusion

between similar sounding or spelled words with different meanings. For example,

a user searching for the term “bark” might be searching for information about tree

bark, but find information only about the sound a dog makes. Controlled

vocabularies reduce the confusion between homonyms.

• Refers user to appropriate terms – From the example above, if a user searches for

“George Bush” in the catalog, the references under the controlled vocabulary

heading will allow the catalog to offer “See under” links, allowing the user to

connect to the specific information they are seeking. In the example, the catalog


might produce links to both George W. Bush and George H. W. Bush, allowing

the user to search more successfully for the particular person (or term).

• Allows for the use of a hierarchy of terms – This allows for easier classification of

terms, as well as collocation, thereby improving the usage of terms in searching.

• Facilitates the use of language independent codes and notation – This allows users

to look at and understand terms in formatting that might not be in their native

language.

However, controlled vocabularies are not perfect, and are less than perfectly

suited to cope with the explosive growth of information today. As the Steele (2009)

article highlights, libraries are receiving information resources faster than they can create

metadata for these items. LCSH is slow to add new headings, or alter current ones to

meet the information needs of users as reflected in the growth of keyword searching.

However, through the growth of social media websites, such as delicious, flickr,

and LibraryThing, an alternate method for assigning metadata to objects has arisen:

tagging, or folksonomies. This is a method by which any user of a website or service can

assign metadata to an item, with no control over vocabulary headings or preferred terms.

Tags can range from the personal, such as “to-read” to the highly descriptive, such as

“libel law,” to the subjective, as in “bad book.” The appeal of these tags lies in the ease of

their creation, as well as the freedom to “tag” an object with any word the user chooses.

Of course, these terms have many different meanings, each specific to the creator but not

necessarily shared with each individual “user” of the tags, meaning a user who did not

create the original tags themselves. This represents a major problem in using

folksonomies in library catalogs – there is no control over subjective terms, or synonyms.

No widespread efforts exist to combine LCSH and folksonomies but some limited studies

have been done of folksonomies, their use in library catalogs, and their possible

combination with LCSH.

In the Bar-Ilan (2008) article, the authors studied the process of assigning tags to

a variety of photos with significance to the users of those items. Specifically, the study

examined two methods of assigning user-generated tags: free form and through fields.

The authors found that structured tagging, or tagging with the use of fields, can provide

more specific metadata, but also creates room for mis-interpretation of those fields. In


addition, the users are tied to only those fixed fields, and are unable to assign free-form

tags to the items, limiting the metadata that users can generate. The authors found this to

be a limitation and suggested a system by which users can both generate the fields, as

well as the metadata entered into those fields so that not only do the users create the

metadata, they also create some type of indication as to how that metadata should be

interpreted and utilized.

Tools for the use of unstructured user-generated tags are highlighted in the

Jeffries (2008) article. In this article, the author highlights four social cataloging services:

Shelfari, Goodreads, Visual bookshelf, and LibraryThing. The author gives a general

overview of each service, as well as highlighting their impact for librarians. Tags are

mentioned, but the value of this article lies in its broad overviews of each service, each

one using tags in a slightly different way. In addition, these social cataloging websites

provide a good look at how a library might implement social tagging in their own catalog.

This is an especially helpful resource to read before reading the Thomas and Mendes

articles about LibraryThing for libraries, discussed later.

The Lawson (2009) article examines the use of both LCSH as well as

folksonomies in library catalogs. As highlighted in the conclusion of the article, tags can

yield far more information about an item than a subject heading can. In the case of one

item studied, there was only one subject heading, but many different tags assigned by

users, each which had (arguably) similar meanings to the subject heading. Lawson argues

for the parallel implementation of both LCSH as well as tags in order to enhance

searching and access points for bibliographic records, noting: “While social tagging does

consist of a great deal of subjective tagging, there is enough objective tagging available

on bibliographic-related websites such as Amazon and LibraryThing that librarians can

use to provide enriched bibliographic records,” (Lawson, 2009, p. 580).

In the article “Subjecting the catalog to tagging,” by Mendes et al (2009), the

authors examine the implementation of a social cataloging tool, LibraryThing, in

conjunction with a library’s catalog, in an iteration called LibraryThing for Libraries

(LTFL). The article discusses some of the problems associated with both controlled

vocabularies, as well as folksonomies, and introduces the concept of leveraging metadata

from third party vendors. The authors then discuss the specifics of implementation of


LTFL in library catalogs. Also included in the article is an analysis of tags and LCSH,

with interesting results. On average, there were only 4.1 LCSH headings per item, but

there were over 30 tags per item. In addition, usage statistics for the user tags are

included, but do not constitute a definitive study of user preferences and trends in using

tags as access points for catalog records.

In his article about emerging trends in tagging, Smith (2008) discusses the advent

of trends in what might be called second generation tagging. He identifies and describes

four areas in which tagging is changing. The first area Smith highlights is that tags are

gaining more structure. This trend allows users to map tags to concepts, so that a user

might differentiate between the bark of a dog and the bark of a tree through the use of

those structures. The second area highlighted is the leveraging of communities. Through

the use of large user communities and large tag pools, users can link any two tags to

make them equivalent. After this is done, the more popular term becomes the preferred

term, much like a heading in LCSH. The third area examined is automanual

folksonomies. Through this implementation of tagging, users can choose from a

predetermined set of tags presented in a hierarchical format, but can also create their own

tags. Finally, the author examines user-generated innovations based on tags. This section

looks at the many ways in which the metadata represented by tags can be used, from an

RSS feed to methods by which users can adapt metadata to better fit their needs.

In his article “The new cooperative cataloging,” Tom Steele (2008) broadly

examines tagging and its use in library catalogs, social cataloging, and tagging websites.

Steele concludes that because the function of a library catalog is to provide access to

information, then tagging has a rightful place in the catalog. He examines how libraries

can utilize tagging within their own catalogs through widely used tagging sites such as

LibraryThing and YouTube, as well as LTFL, mentioned above. In addition, Steele

suggests that libraries can also implement their own independent tagging systems. These

systems would allow libraries to implement tags in a manner that best fits their users.

The Thomas (2009) article compares social tags to LCSH and looks specifically at

what extent tags could replace LCSH. The advantages and disadvantages of both systems

are examined in the article. The authors examine ten books in this process and found that

“social tagging does indeed augment the LCSH providing additional access to resources.


Tags do supply additional vocabulary that could be incorporated into LCSH,” (Thomas,

2009, p. 431). Important to note, though, is that the authors decline to state that social

tags can entirely replace LCSH, simply augment that system of controlled vocabulary.

The authors propose that a hybridization of tagging and LCSH might be the best use of

tags, especially when the tags used are high in number and have been in use for a longer

time, such as the tags generated in LTFL.

The final article discussed in this review is the Yi and Chan (2009) article about

an exploratory study done examining the linking of folksonomy to LCSH. For this study,

the authors used tags generated from Delicious, a social tagging website, and compared

those tags to LCSH. The authors found that approximately ten percent of the compared

tags had no matching terms in LCSH. In addition, the authors describe the difficulties in

linking LCSH and social tags in an effective manner, including the “occurrence of many

specific technology-related tags, most of which were not found in LCSH; pervasiveness

of inconsistent forms and patterns of multiword tags that result in failure in matching

headings; and incompatibility between word forms such as abbreviations or acronyms

used in tags and terms in LCSH,” (Yi, 2009, p. 897).

A review of the literature above produces two ways in which libraries can utilize

and implement social tagging at the present time. The first manner in which libraries can

use social tags in their catalogs is through a parallel implementation in the catalog with

LCSH. These different systems would appear simultaneously upon the display of a record

and would both be independently searchable in the OPAC. The other method by which

libraries can use social tags is through linking those tags to, or incorporating them with,

LCSH. This linked system would require some type of infrastructure support from LCSH,

either through the incorporation of social tags into the controlled vocabulary or through

the linking of tags to a heading in LCSH.

The first method mentioned above, parallel deployment, appears to be the easiest

to implement in library catalogs. No alteration of LCSH is needed, nor is the library

required to do additional work to link social tags to the LCSH. This allows the library to

reap some of the benefits of social tags discussed in the articles while reducing the

amount of work needed to implement the tags. However, this system is less than optimal

for the user of the catalog. Two systems for subject description have the potential to be


confusing to the user. Furthermore, tags can become unwieldy, unless a system for

management is in place, which ostensibly would be implemented and maintained by the

library.

The second method mentioned above, linked or integrated deployment, has the

potential to be the best implementation of social tagging for the user. This method

presents the user with a familiar, unified subject description system with the added

benefits of being integrated with the LCSH. Integration helps reduce many of the

problems associated with “pure” free-form tagging: lack of specificity, poor synonym

control, references to preferred terms, lack of collocation and hierarchy, as well as

discrimination among homonyms. This system would also draw on the metadata already

held within LCSH, one of the largest systems of controlled vocabulary in use today.

However, there are problems with the implementation of a linked-type system. Before

this could be implemented, the very fabric of LCSH would need to be changed to allow

the addition and usage of social tags as synonyms, or new headings. In addition, libraries

would need to update the headings in their catalogs in a much more timely fashion than is

generally done now, so that the changes brought by added tags could be used to improve

the access points for records in the catalog.

In conclusion, social tags simply provide too much data about the items they

represent to be ignored by libraries. They provide an interesting way by which users can

“get involved” at their library, even though they might not leave their own homes.

Literature about the topic is helpful, but efforts to integrate social tags into library

catalogs are really in their infantile stages. At this point, two courses of action are

available to libraries, both requiring monumental amounts of work to implement

effectively. Later versions and implementations of social tags in catalogs will yield

greater benefits for users, but major change will not happen until the library community

examines whether or not LCSH and social tags should be mutually exclusive, or should

be integrated in some meaningful way.


References

Bar-Ilan, J., Shoham, S., Idan, A., Miller, Y., & Shachak, A. (2008). Structured versus

unstructured tagging: a case study. Online Information Review, 32(5), 635-647.

Jeffries, S. (2008). Social cataloging tools: a comparison and application for librarians.

Library Hi Tech News, 25(10), 1-4.

Lawson, K. G. (2009). Mining social tagging data for enhanced subject access for readers

and researchers. The Journal of Academic Librarianship, 35(6), 574-582.

Macgregor, G., McCulloch, E. (2006). Collaborative tagging as a knowledge organization

and resource discovery tool. Library Review, 55(5), 291-300.

Mendes, L. H., Quiñonez-Skinner, J., Skaggs, D. (2009). Subjecting the catalog to

tagging. Library Hi Tech, 27(1), 30-41.

Smith, G. (2008). Tagging: emerging trends. Bulletin of the American Society for

Information Science and Technology, 34(6), 14-17.

Steele, T. (2009). The new cooperative cataloging. Library Hi Tech, 27(1), 68-77/

Thomas, M., Caudle, D. M., Schmitz, C. M. (2009). To tag or not to tag? Library Hi

Tech, 27(3), 411-434.

Yi, K., Chan, L. M. (2009) Linking folksonomy to Library of Congress subject headings:

an exploratory study. Journal of Documentation, 65(6) 872-900.

Social Tagging, Library of Congress’ Subject Headings, and Library Catalogs

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