Definition and Use
As stated simply in Merriam-Webster Online, an index is essentially “a list (as of bibliographical information or citations to a body of literature) arranged usually in alphabetical order of some specified datum (as author, subject, or keyword)” (2006). Items in an index point to where the information being listed can be found, either within a document, a work, or a collection of works. As mentioned in Richardson’s discussion of the knowledge base used in reference work, indexes meet the demand for access to current and up-to-date information, which is generally found in periodicals and serials rather than the recent information found in books (1995, p. 162-163).
Index Forms and Formats
Indexes may be issued as a stand-alone print or electronic source, such as stand-alone indexes to periodical literature in certain subjects, or they may be included within a document itself, such as in the index portion located in the back of the book. Electronic indexes often provide more access points than the traditional print indexes. Several electronic indexes may be aggregated into one database, provided by a publisher or private indexing service, so that searches may be conducted across several individual indexes at one time. Many indexes provide direct links to holdings in the online library catalog or to licensed access; some aggregated services provide access to full-text documents.
Types of Indexes
Indexes are primarily an access and research tool. Whereas most library catalogs provide records with access to larger information carriers (books, serials, electronic resources, etc.), indexes give users access to information at the document level within a given field or grouping. As Dalrymple asserted, how groups of document are chosen for an index “may be determined by a variety of criteria; topic, language, publication type, and country of origin are some of the most common” (2001, p. 73). The most common type of indexes are those published for periodicals.
Some other common types of indexes, as outlined by Linda C. Smith (2001) in her article on indexes and abstracts include:
- Table of Contents Services. Where “tables of contents are grouped together in broad subject classes, and a simple keyword subject index provides access to article titles.” For example, Current Contents Connect (p. 517)
- Newspaper Indexes. Such as the New York Times Index (p. 518)
- Broad Subject Periodical Indexes. Such as PAIS International in Print (p. 519)
- Citation Indexes. Such as the Social Sciences Citation Index (p. 520)
- Indexes for Special Types of Materials. Such as indexes on dissertations, for example: Comprehensive Dissertation Index (p. 523).
- Indexes of Reviews. To “assist the user in location reviews of books or nonprint materials, such as films and software.” Such as the Book Review Index (p. 524).
- Indexes for Different Literary Forms. Such as the Play Index and the Short Story Index (pp. 527-528).
Many indexes also include abstracts or shorter annotations.
The terms indexes use may be controlled (also known as controlled vocabulary, controlled indexing languages, or assigned-term systems) or uncontrolled (also known as natural-indexing languages or derived-term systems) (alternative terms taken from Rowley and Farrow, 2000, p. 125-126). In controlled language systems, subject terms and topics (often called descriptors in indexing) are assigned from a controlled list or a thesaurus. In uncontrolled language systems, “all descriptors are taken from the document being indexed” (Rowley and Farrow, p. 126-127). These two types of languages are not mutually exclusive, some indexes make use of both.
Individual terms may also be combined to form complex subject terms or descriptors. There are two basic systems for combining search terms: Pre-coordinated systems are subject strings that are coordinated prior to the user’s search to give access to complex topics, such as “Librarianship in the United States” (rather than just Librarianship). Post-coordinated systems are systems where simple descriptors are automatically brought together by the aid of the computer, or, by the user’s commands at the time of the search (such as a Boolean search on simple descriptors). Terms in a search string may also be rotated or reorganized (see http://lu.com/odlis for the definitions of KWAC, KWIC, and KWOC indexing).
The ALA Glossary (1983) lists an abstract as “an abbreviated, accurate representation of a work, usually without added interpretation or criticism, accompanied by a bibliographic reference to the original work when appearing separately from it” (p. 1).
Types of Abstracts
Abstracts can be informative or indicative. “Informative abstracts include salient data from the original. Indicative or descriptive abstracts indicate that such data and other information can be found in the original.” (Bernier, 2003, p. 1).
Abstracts may be written by the author of the document, the journal or publisher issuing the document, or an independent abstracting service. Abstracts may precede a document, or may stand alone in database (or printed resource) of abstracts. Abstracts may also precede or follow citations in an indexing and abstracting database.
REFERENCE LIBRARIAN DUTIES ASSOCIATES WITH INDEXES AND ABSTRACTS
Since they are a reference tool, reference librarians often search indexes and abstracts, and must become familiar with the idiosyncrasies of the indexes used most often in the library. Librarians must be able to quickly assess the layout and scope of an index or abstract on the fly, so to speak. As there is not one standard for the layout or index terms used across different indexes, reference librarians often compile quick reference guides for a group of indexes to aid users. Reference librarians also assist users in finding the right indexes for their query, and often assist users in searching and navigating indexes. Depending on the linking capabilities of the library system, librarians usually work in tandem with the local library catalog, showing the user how to look up titles found in the index. Lastly, reference librarians often play a role in the selection, assessment, and de-selection of indexes in the library's collection.
INDEXING AND ABSTRACTING SERVICES AND FULL TEXT ACCESS
As mentioned above, in the online environment, indexes, abstracts, and even full text can be brought together, and are often available together through an Indexing and Abstracting Service. Publishers may also now provide such content online, separate from the indexing and abstracting services. To this end, Smith (2001) argues that reference librarians should “be aware of the different models of supplying full text that have emerged in the Web environment: publisher-supplied full-text; third-party, or aggregator-supplied full text (e.g. Wilson Omnifile), and distributed, 'linked' full text, in which an indexing and abstracting service links to publisher-supplied full text” (p. 514). In addition to knowing who the provider of the information is, Smith (2001) argues that users should understand that “full text” means different things in different services, as some providers may choose not to include full abstracts, advertisements, sidebars, or other things included with the original text (p. 514). It is important to note that illustrations are also sometimes left out of “full text” articles, though they may contain some textual content and/or provide diagrams needed to fully follow the text, so users do not always get the full document as it was published in its print form.
Bernier, C.L. (2003). Abstracts and abstracting. In Drake, M.A. (Ed.), Encyclopedia of Library and Information Science (Vol. 1, 2nd ed., pp. 1-15).
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Dalrymple, P.W. (2001). Bibliographic control, organization of information, and search strategies. In Bopp, R.E. & Smith, L.C. (Eds.), Reference and
Information Services: An introduction (pp. 69-96). Englewood, Colorado: Libraries Unlimited.
Merriam-Webster Inc. (2006). Merriam-Webster Online. Retrieved Nov. 20, 2006 at: http://www.m-w.com
Reitz, J.M. (n.d.). ODLIS: Online Dictionary for Library and Information Science. Libraries Unlimited. Retrieved November 20, 2006 at:
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Rowley, J. & Farrow, J. (2000). Organizing knowledge: An introduction to managing access to information (3rd ed.). Burlington, Vermont: Gower.
Smith, L.C. (2001). Indexes and Abstracts. In Bopp, R.E. & Smith, L.C. (Eds.), Reference and Information Services: An introduction (pp. 69-96).
Englewood, Colorado: Libraries Unlimited.
Wedgeworth, A. (Ed.). (1986). ALA world encyclopedia of library and information services (2nd ed). Chicago: American Library Association.
Young, H. (Ed.). (1983). The ALA glossary of library and information science. Chicago: American Library Association.