Search (124 results, page 6 of 7)

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Abstract

We investigated how citations from documents labeled by the Institute for Scientific Information (ISI) as "editorial material" contribute to the impact factor of academic journals in which they were published. Our analysis is based on records corresponding to the documents classified by the ISI as editorial material published in journals covered by the Social Sciences Citation Index between 1999 and 2003 (50,273 records corresponding to editorial material published in 2,374 journals). The results appear to rule out widespread manipulation of the impact factor by academic journals publishing large amounts of editorial material with many citations to the journal itself as a strategy to increase the impact factor.

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Abstract

This study explores the tendency of authors to recite themselves and others in multiple works over time, using the insights gained to build citation theory. The set of all authors whom an author cites is defined as that author's citation identity. The study explains how to retrieve citation identities from the Institute for Scientific Information's files on Dialog and how to deal with idiosyncrasies of these files. As the author's oeuvre grows, the identity takes the form of a core-and-scatter distribution that may be divided into authors cited only once (unicitations) and authors cited at least twice (recitations). The latter group, especially those recited most frequently, are interpretable as symbols of a citer's main substantive concerns. As illustrated by the top recitees of eight information scientists, identities are intelligible, individualized, and wide-ranging. They are ego-centered without being egotistical. They are often affected by social ties between citers and citees, but the universal motivator seems to be the perceived relevance of the citees' works. Citing styles in identities differ: "scientific-paper style" authors recite heavily, adding to core; "bibliographic-essay style" authors are heavy on unicitations, adding to scatter; "literature-review style" authors do both at once. Identities distill aspects of citers' intellectual lives, such as orienting figures, interdisciplinary interests, bidisciplinary careers, and conduct in controversies. They can also be related to past schemes for classifying citations in categories such as positive-negative and perfunctory- organic; indeed, one author's frequent recitation of another, whether positive or negative, may be the readiest indicator of an organic relation between them. The shape of the core-and-scatter distribution of names in identities can be explained by the principle of least effort. Citers economize on effort by frequently reciting only a relatively small core of names in their identities. They also economize by frequent use of perfunctory citations, which require relatively little context, and infrequent use of negative citations, which require contexts more laborious to set

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Abstract

We here perform an analysis of all 1128 publications produced by scientists during their employment at the University of Texas Institute for Geophysics, a geophysical research laboratory founded in 1972 that currently employs 23 Ph.D.-level scientists. We thus assess research performance using as bibliometric indicators such statistics as publications per year, citations per paper, and cited half-lives. To characterize the research style of individual scientists and to obtain insight into the origin of certain publication-counting discrepancies, we classified the 1128 publications into four categories that differed significantly with respect to statistics such as lifetime citation rates, fraction of papers never-cited after 10 years, and cited half-life. The categories were: mainstream (prestige journal) publications -32.6 lifetime cit/pap, 2.4% never cited, and 6.9 year half-life; archival (other refereed)-12.0 lifetime cit/pap. 21.5% never cited, and 9.5 years half-life; articles published as proceedings of conferences-5.4 lifetime cit/pap, 26.6% never cited, and 5.4 years half-life; and "other" publications (news articles, book reviews, etc.)-4.2 lifetime cit/pap, 57.1% never cited, and 1.9 years half-life. Because determining cited half-lives is highly similar to a well-studied phenomenon in earthquake seismology, which was familiar to us, we thoroughly evaluate five different methods for determining the cited half-life and discuss the robustness and limitations of the various methods. Unfortunately, even when data are numerous the various methods often obtain very different values for the half-life. Our preferred method determines halflife from the ratio of citations appearing in back-to-back 5-year periods. We also evaluate the reliability of the citation count data used for these kinds of analysis and conclude that citation count data are often imprecise. All observations suggest that reported differences in cited half-lives must be quite large to be significant

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Abstract

Many authors have posited a social component in citation, the consensus being that the citers and citees often have interpersonal as well as intellectual ties. Evidence for this belief has been rather meager, however, in part because social networks researchers have lacked bibliometric data (e.g., pairwise citation counts from online databases), and citation analysts have lacked sociometric data (e.g., pairwise measures of acquaintanceship). In 1997 Nazer extensively measured personal relationships and communication behaviors in what we call "Globenet," an international group of 16 researchers from seven disciplines that was established in 1993 to study human development. Since Globenet's membership is known, it was possible during 2002 to obtain citation records for all members in databases of the Institute for Scientific Information. This permitted examination of how members cited each other (intercited) in journal articles over the past three decades and in a 1999 book to which they all contributed. It was also possible to explore links between the intercitation data and the social and communication data. Using network-analytic techniques, we look at the growth of intercitation over time, the extent to which it follows disciplinary or interdisciplinary lines, whether it covaries with degrees of acquaintanceship, whether it reflects Globenet's organizational structure, whether it is associated with particular in-group communication patterns, and whether it is related to the cocitation of Globenet members. Results show cocitation to be a powerful predictor of intercitation in the journal articles, while being an editor or co-author is an important predictor in the book. Intellectual ties based an shared content did better as predictors than content-neutral social ties like friendship. However, interciters in Globenet communicated more than did noninterciters.

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Abstract

This article explores the status of research in hydrogeology using data mining techniques. First we try to explain what citation analysis is and review some of the previous work on citation analysis. The main idea in this article is to address some common issues about citation numbers and the use of these data. To validate the use of citation numbers, we compare the citation patterns for Water Resources Research papers in the 1980s with those in the 1990s. The citation growths for highly cited authors from the 1980s are used to examine whether it is possible to predict the citation patterns for highly-cited authors in the 1990s. If the citation data prove to be steady and stable, these numbers then can be used to explore the evolution of science in hydrogeology. The famous quotation, "If you are not the lead dog, the scenery never changes," attributed to Lee Iacocca, points to the importance of an entrepreneurial spirit in all forms of endeavor. In the case of hydrogeological research, impact analysis makes it clear how important it is to be a pioneer. Statistical correlation coefficients are used to retrieve papers among a collection of 2,847 papers before and after 1991 sharing the same topics with 273 papers in 1991 in Water Resources Research. The numbers of papers before and after 1991 are then plotted against various levels of citations for papers in 1991 to compare the distributions of paper population before and after that year. The similarity metrics based on word counts can ensure that the "before" papers are like ancestors and "after" papers are descendants in the same type of research. This exercise gives us an idea of how many papers are populated before and after 1991 (1991 is chosen based on balanced numbers of papers before and after that year). In addition, the impact of papers is measured in terms of citation presented as "percentile," a relative measure based on rankings in one year, in order to minimize the effect of time.

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Abstract

Much has been written about the potential and pitfalls of macroscopic Web-based link analysis, yet there have been no studies that have provided clear statistical evidence that any of the proposed calculations can produce results over large areas of the Web that correlate with phenomena external to the Internet. This article attempts to provide such evidence through an evaluation of Ingwersen's (1998) proposed external Web Impact Factor (WIF) for the original use of the Web: the interlinking of academic research. In particular, it studies the case of the relationship between academic hyperlinks and research activity for universities in Britain, a country chosen for its variety of institutions and the existence of an official government rating exercise for research. After reviewing the numerous reasons why link counts may be unreliable, it demonstrates that four different WIFs do, in fact, correlate with the conventional academic research measures. The WIF delivering the greatest correlation with research rankings was the ratio of Web pages with links pointing at research-based pages to faculty numbers. The scarcity of links to electronic academic papers in the data set suggests that, in contrast to citation analysis, this WIF is measuring the reputations of universities and their scholars, rather than the quality of their publications

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Abstract

In one of two bibliometric papers in this issue Brown looks at formal publication and citation of Eprints as shown by the policies and practices of 37 top tier physics journals, and by citation trends in ISI's SciSearch database and Journal Citation Reports. Citation analysis was carried out if Eprint cites were indicated by editor response, instruction to authors sections, reports in the literature, or actual examination of citation lists. Total contribution to 12 archives and their citation counts in the journals were compiled. Of the 13 editors surveyed that responded, 8 published papers that had appeared in the archive. Two of these required removal from the archive at publication; two of the 13 did not publish papers that have appeared as Eprints. A review journal that solicits its contributions allowed citation of Eprints. Seven allowed citations to Eprints, but were less than enthusiastic.Nearly 36,000 citations were made to the 12 archives. Citations to the 37 journals and their impact factors remain constant over the period of 1991 to 1998. Eprint citations appear to peak about 3 years after appearance as do citations to published papers. Contribution to the archives, and their use as measured by citation, is clearly growing. Citation form and publishing policy varies from journal to journal.

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Abstract

References from publications are at the same time citations to other publications. This entry introduces some of the practical uses of citation data in science and scholarship. At the individual level citations identify and permit the retrieval of specific editions of works, while also suggesting their subject matter, authority, and age. Through citation indexes, retrievals may include not only the earlier items referred to by a given work, but also the later items that cite that given work in turn. Some technical notes on retrieval are included here. Counts of citations received over time, and measures derived from them, reveal the varying impacts of works, authors, journals, organizations, and countries. This has obvious implications for the evaluation of, e.g., library collections, academics, research teams, and science policies. When treated as linkages between pairs of publications, references and citations reveal intellectual ties. Several kinds of links have been defined, such as cocitation, bibliographic coupling, and intercitation. In the aggregate, these links form networks that compactly suggest the intellectual histories of research specialties and disciplines, especially when the networks are visualized through mapping software. Citation analysis is of course not without critics, who have long pointed out imperfections in the data or in analytical techniques. However, the criticisms have generally been met by strong counterarguments from proponents.

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