Metadata Schemas

A metadata schema is the underlying organizational pattern or framework for the metadata, which consists of pre-defined elements representing the specific characteristics of an information resource. Examples of pre-defined metadata elements include title, creator, creation date, and other related bibliographic features. It is important to recognize that there is no single, comprehensive schema for metadata. Instead, there are different types of schemas, each created for specific types of information according to their own set of standardized guidelines.

Although individual schemas are controlled and standardized, there can be a significant amount of variation among the different schemas created by different institutions. Flexibility refers to the ability of the metadata creators to determine the level of detail contained within a record. Consequently, not all schemas possess the same levels of detail. As a result, schemas can vary in the number and types of metadata elements used, in the use of controlled vocabularies, and in encoding into machine-readable form (Taylor, 2004, p. 142). Additionally, it has become increasingly difficult to distinguish the bibliographic features of resources of different types of media and formats when compared to traditional print materials (Kim, 2003, p. 103).

Most schemas, however, do tend to exhibit three common traits: structure, semantics, and syntax. Structure refers to the model that coordinates the data, ultimately arranging how the data is presented. Semantics refers to the meaning associated with the pre-defined metadata elements that compose the schema. For example, does the meaning of the term “author” used in one schema correspond to the meaning of the term “creator” used in another? Syntax refers to how the metadata elements are to be encoded into machine-readable form. The encoding allows the metadata to be processed by a computer program. Unless the encoding scheme understands the semantics of the metadata schema, the data will be unusable (Taylor, 2003). Discrepancies among element meanings and incompatibility among encoding formats of different schemas usually result in interoperability issues.

References

Kim, K. (2003). Recent work in cataloging and classification, 2000-2002. Library Resources and Technical Services, 47(3), 96-109. Retrieved May 20, 2008, from InfoTrac OneFile database.
Taylor, A.G. (2004). The organization of information (2nd ed.). Westport, CN: Libraries Unlimited.
Taylor, C. (2003). An introduction to metadata. Retrieved May 20, 2008, from http://www.library.uq.edu.au/iad/ctmeta4.html

Metadata Defined

Metadata can be broadly defined as “data about data.” Metadata is structured data that describes the bibliographic attributes of an information resource. Any organizable unit of information can be considered an information resource, such as a book, a website, an audio file, a video, an image, and so on (Taylor, 2004, p. 139). Regardless of the medium or format for an information resource, metadata serves to facilitate the discovery, description, management, retrieval, and preservation of a unit of information.

According to the International Federation of Library Associations' (IFLA) Functional Requirements for Bibliographic Records, metadata has four primary objectives:
1. To assist users in finding desired information resources
2. To help users in identifying similar information resources and distinguishing them from one another
3. To aid users in selecting the appropriate materials suitable to their needs
4. To provide uses with the information necessary to obtain or access the desired resource
Based on these objectives, usability in information retrieval systems as well as user needs must be considered when creating metadata (Taylor, 2004, p. 146).

Accordingly, metadata is used in conjunction with information retrieval tools to identify, discover, manage, and retrieve information resources. Using this definition, a very simple and familiar example of metadata would be a card catalog record describing information about a book, since the primary purpose of the descriptive data contained in the record is to facilitate the discovery, description, and retrieval of the book.

In this example, it is evident that the idea of metadata is not a new concept to library and information science. However, modern technology has enabled bibliographic items to be published in a variety of formats. Therefore, the term metadata is applicable to all information resources regardless of media or format. Consequently, the term is now commonly used in regards to digital and electronic information, in addition to print resources (Yousefi & Yousefi, 2007). Moreover, with the advent of computer technology, metadata is now applied to electronic and online information retrieval systems (Herner, 1984, p. 162).

References

Herner, S. (May 1984). Brief history of information science. Journal of the American Society for Information Science, 35(3), 157-163. Retrieved May 18, 2008, from Wiley Interscience database.
Taylor, A.G. (2004). The organization of information (2nd ed.). Westport, CT: Libraries Unlimited.
Yousefi, A., & Yousefi, S. (2007). Metadata: A new word for an old concept. Library Philosophy and Practice. Retrieved May 20, 2007, from InfoTrac OneFile database.

Introduction

The development of computers revolutionized the way in which information can be retrieved. In 1945, Vannevar Bush envisioned, among other things, “a machine for the storage and retrieval of documents” in his article “As We May Think” (Rubin, 2004, p. 34). With the increasing use of computers throughout the twentieth century, the field of information science experienced a change in the way information was accessed- “a shift in emphasis away from the item that held the information to an emphasis on accessing the content of the information” (Rubin, 2004, p. 34). But how does one decipher which content is relevant to one’s information needs? Simply stated, metadata provides the descriptive information about resources to aid in the discovery, identification, management, retrieval, and preservation of units of information (Taylor, 2004, p. 139). While the concept of metadata is not new to library and information science, it continues to evolve with computer technology into the twenty-first century.

References

Bush, V. (1945). As we may think. Atlantic Monthly, 176, 101-108. Retrieved May 14, 2008, from http://www.ps.uni-sb.de/~duchier/pub/vbush/vbush-all.shtml.
Rubin, R.E. (2004). Foundations of library and information science (2nd ed.). New York: Neal-Schuman.
Taylor, A.G. (2004). The organization of information (2nd ed.). Westport, CT: Libraries Unlimited.