Citation Index

23/05/2013 – 7:44 am
Tony McCall

A citation index is an index of citations between publications, allowing the user to easily discern which later documents cite which earlier documents.

The first citation indices were legal citators such as Shepard’s Citations (1873). In 1960, Eugene Garfield’s Institute for Scientific Information (ISI) introduced the first citation index for papers published in academic journals, starting with the Science Citation Index (SCI), and later expanding to produce the Social Sciences Citation Index (SSCI) and the Arts and Humanities Citation Index (AHCI). As of 2006, there are other sources of such data, such as Google Scholar.

Citations are used as a measure of importance or relative value of the information source, such as an individual journal article, book, and others. For example, if an article is frequently cited by other journal articles and books in the discipline, it may indicate the relative importance of a work. Citation impact analysis is called bibliometrics in library and information science and has a wide range of applications.

Citation analysis

A citation is the act of acknowledging or citing the author, year, title, and locus of publication (journal, book, or other) of a source used in a published work. Such citations can be counted as measures of the usage and impact of the cited work. This is called citation analysis or bibliometrics (see below). Among the measures that have emerged from citation analysis are the citation count for

An individual article (how often it was cited)
An author (total citations, or average citation count per article)
For a journal (journal impact factor, or the average citation count for the articles in the journal)

Citation counts are correlated with other measures of scholarly/scientific performance and impact and can in some cases be enhanced by making a work open access by self-archiving the complete article on the web, publishing it in an open access journal, or publishing it as an Open access article in one of the Hybrid open access journals.

There also exists an H-index measure of an individual scientist’s impact and citation record.

Major current citation indexing services

There are two publishers of general-purpose academic citation indexes, available to libraries by subscription:

ISI is now part of Thomson Scientific. Though the ISI citation indexes are still published in print and compact disc, they are now generally accessed through the Web under the name Web of Science, which is in turn part of the group of databases in WoK.
Elsevier publishes Scopus, available online only, which similarly combines subject searching with citation browsing and tracking in the sciences and social sciences.

There are a number of other indexes, more readily available. Some of the currently notable ones are:

The CiteSeer system provides citation and other searching of scientific literature, primarily in the fields of computer and information science.
RePec provides this in economics, and other discipline-specific indexes have also begun to include it in their indexes. Even journal publishers often supply the facility to link to late citations, at least from the journals they publish.
Google Scholar (GS) has citation functionality, limited to the recent articles that are included. There is already discussion about the possibility that GS may in the future have sufficient capabilities to make the commercial products unnecessary.

Each of these products offer an index of citations between publications and a mechanism to establish which documents cite which other documents. The different products offer different ways to access the citation list and also display their citation index differently. They differ widely in cost: WOK and Scopus are among the highest-cost subscription databases; the others mentioned are free.

More at:

source: Citation index. (2013, May 22). New World Encyclopedia, . Retrieved 21:40, May 22, 2013 from

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