Search (69 results, page 1 of 4)

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Abstract

Over a 35-year period, Irving H. Sher played a critical role in the development and implementation of the Science Citation Index and other ISI products. Trained as a biochemist, statistician, and linguist, Sher brought a unique combination of talents to ISI as Director of Quality Control and Director of Research and Development. His talents as a teacher and mentor evoked loyalty. He was a particularly inventive but self-taught programmer. In addition to the SCI, Social Sciences Citation Index, and Arts and Humanities Citation Index,

Date

16.12.2001 14:01:22

Object

Science Citation Index
Social Sciences Citation Index
Arts and Humanities Citation Index

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Abstract

Conclusion There is a reason why Google Scholar and Web of Science/Scopus are kings of the hills in their various arenas. They have strong brand recogniton, a head start in development and a mass of eyeballs and users that leads to an almost virtious cycle of improvement. Competing against such well established competitors is not easy even when one has deep pockets (Microsoft) or a killer idea (scite). It will be interesting to see how the landscape will look like in 2030. Stay tuned for part II where I review each particular index.

Date

17.11.2020 12:22:59

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Abstract

This article challenges recent research (Evans, 2008) reporting that the concentration of cited scientific literature increases with the online availability of articles and journals. Using Thomson Reuters' Web of Science, the present article analyses changes in the concentration of citations received (2- and 5-year citation windows) by papers published between 1900 and 2005. Three measures of concentration are used: the percentage of papers that received at least one citation (cited papers); the percentage of papers needed to account for 20%, 50%, and 80% of the citations; and the Herfindahl-Hirschman index (HHI). These measures are used for four broad disciplines: natural sciences and engineering, medical fields, social sciences, and the humanities. All these measures converge and show that, contrary to what was reported by Evans, the dispersion of citations is actually increasing.

Date

22. 3.2009 19:22:35

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Object

Science Citation Index

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Abstract

Announces the availability of the Web of Science, a proprietary Web browser providing intranet access to the Citation Index databases from ISI. The new browser interface will allow researcher to browse indexed information and perform further research. Describes search options

Object

Science citation index
Social sciences citation index

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Abstract

The h-index (Hirsch, 2005) is robust, remaining relatively unaffected by errors in the long tails of the citations-rank distribution, such as typographic errors that short-change frequently cited articles and create bogus additional records. This robustness, and the ease with which h-indices can be verified, support the use of a Hirsch-type index over alternatives such as the journal impact factor. These merits of the h-index apply both to individuals and to journals.

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Abstract

The debate about which similarity measure one should use for the normalization in the case of Author Co-citation Analysis (ACA) is further complicated when one distinguishes between the symmetrical co-citation - or, more generally, co-occurrence - matrix and the underlying asymmetrical citation - occurrence - matrix. In the Web environment, the approach of retrieving original citation data is often not feasible. In that case, one should use the Jaccard index, but preferentially after adding the number of total citations (i.e., occurrences) on the main diagonal. Unlike Salton's cosine and the Pearson correlation, the Jaccard index abstracts from the shape of the distributions and focuses only on the intersection and the sum of the two sets. Since the correlations in the co-occurrence matrix may be spurious, this property of the Jaccard index can be considered as an advantage in this case.

Object

Salton's Cosine index
Jaccard index

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Abstract

The Web of Science, an online database of bibliographic information produced by Thomson Reuters- draws its real value from the scholarly citation index at its core. By indexing the cited references from each paper as a separate part of the bibliographic data, a citation index creates a pathway by which a paper can be linked backward in time to the body of work that preceded it, as well as linked forward in time to its scholarly descendants. This entry provides a brief history of the development of the citation index, its core functionalities, and the way these unique data are provided to users through the Web of Science.

Object

Science Citation Index
Social Sciences Citation Index
Arts and Humanities Citation Index

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Footnote

Ein Leserbrief zu Sinn und Nutzen des Science Citation Index als Erwiderung auf einen Beitrag von A. Octavio in Mathematical intelligencer 18(1996) no.4, S.9-11

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Object

Science citation index
Social sciences citation index

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Abstract

The invention of the citation index was credited to Shepard (1873) and Shapiro described a legal citation index published in 1743. A similar index was embedded in the Talmud 2 centuries earlier (1546). The 1st Hebrew citation index to a printed book is dated 1511. The earliest Hebrew manuscript citation index, ascribed to Maimonides, dates from the 12th century. Considerable knowledge was assumed for users of these tools. The substantial knowledge of their compilers contrats with the semi-automatic production of modern citation indexes. The terms citation, quotation, reference, cross-reference, locator, and concordance are employed inconsistently in publications about Hebrew indexes. There is a lack of citation links between the secondary literature on Hebrew indexes and that of citation analysis

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Abstract

The possibilities of using the Arts & Humanities Citation Index (A&HCI) for journal mapping have not been sufficiently recognized because of the absence of a Journal Citations Report (JCR) for this database. A quasi-JCR for the A&HCI ([2008]) was constructed from the data contained in the Web of Science and is used for the evaluation of two journals as examples: Leonardo and Art Journal. The maps on the basis of the aggregated journal-journal citations within this domain can be compared with maps including references to journals in the Science Citation Index and Social Science Citation Index. Art journals are cited by (social) science journals more than by other art journals, but these journals draw upon one another in terms of their own references. This cultural impact in terms of being cited is not found when documents with a topic such as digital humanities are analyzed. This community of practice functions more as an intellectual organizer than a journal.

Object

Arts and Humanities Citation Index

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Abstract

Analyses 6 indicators of the Science Citation Index Journals Citation Reports over a 19 year period: number of total citations, number of citations to the previous 2 years, number of source items, impact factor, immediacy index and cited half life. Proposes a box plot method to aggregate the values of each indicator so as to obtain at a glance portrayals of the JCR population from 1974 to 1993. This 'rereading' of the JCR, which presents the JCR product differently, makes it possible to shed new light on the large sub population of journals not at the top of the rankings

Issue

1. Description of the JCR journal population based on the number of citations received, number of source items, impact factor, immediacy index and cited half life

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Object

Science Citation Index
Social Sciences Citation Index
Arts and Humanities Citation Index

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Object

Science citation index
Social sciences citation index
Arts and humanities citation index

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Abstract

Indexes in general seek to provide a "key" to a body of literature intending to help the user in identifying, verifying, and/or locating individual or related items. The most common devices for collocation in indexes are authors' names and subjects. A different approach to collocating related items in an index is provided by a method called "citation indexing." Citation indexes attempt to link items through citations or references, in other works, by bringing together items cited in a particular work and the works citing a particular item. Citation indexing is based an the concept that there is a significant intellectual link between a document and each bibliographic item cited in it and that this link is useful to the scholar because an author's references to earlier writings identify relevant information to the subject of his current work. One of the major differences between the citation index and the traditional subject index is that the former, while listing current literature, also provides a retrospec tive view of past literature. While each issue of a traditional index is normally concerned only with the current literature, the citation index brings back retrospective literature in the form of cited references, thereby linking current scholarly works with earlier works. The advantages of the citation index have been considered to be its value as a tool for tracing the history of ideas or discoveries, for associating ideas between current and past work, and for evaluating works of individual authors or library collections. The concept of citation indexing is not new. It has been applied to legal literature since 1873 in a legal reference tool called Shepard's Citations. In the 1950s Eugene Garfield, a documentation consultant and founder and President of the Institute for Scientific Information (Philadelphia), developed the technique of citation indexing for scientific literature. This new application was facilitated by the availability of computer technology, resulting in a series of services: Science Citation Index (1955- ), Social Sciences Citation Index (1966- ), and the Arts & Humanities Index (1976- ). All three appear in printed versions and as machine-readable databases. In the following essay, the first in a series of articles and books elucidating the citation indexing system, Garfield traces the origin and beginning of this idea, its advantages, and the methods of preparing such indexes.

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Abstract

This paper examines the probability structure of the 2005 Science Citation Index (SCI) and Social Sciences Citation Index (SSCI) Journal Citation Reports (JCR) by analyzing the Impact Factor distributions of their journals. The distribution of the SCI journals corresponded with a distribution generally modeled by the negative binomial distribution, whereas the SSCI distribution fit the Poisson distribution modeling random, rare events. Both Impact Factor distributions were positively skewed - the SCI much more so than the SSCI - indicating excess variance. One of the causes of this excess variance was that the journals highest in the Impact Factor in both JCRs tended to class in subject categories well funded by the National Institutes of Health. The main reason for the SCI Impact Factor distribution being more skewed than the SSCI one was that review journals defining disciplinary paradigms play a much more important role in the sciences than in the social sciences.

Object

Science Citation Index
Social Sciences Citation Index