Power Law Relations in Science Bibliography—a Self‐consistent Interpretation

Naranan, S.

doi:10.1108/eb026510

Cited by 68 publications

(37 citation statements)

References 13 publications

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“…1B). This is a distribution of the extreme-property (topnormal, i.e., corresponding to the top end of a normal distribution) type previously demonstrated for citations to individual authors (Seglen, 1992a) and individual journals (Seglen, 1989a;1992b) rather than of the Lotka type (with doublelogarithmic linearity) found for citations to whole scientific fields (Magyar, 1973;Naranan, 1971) and other complex assemblies (Price, 1965;Folly et al, 1981). The study population thus appears to be more uniform than the (probably topnormally distributed) population of scientists usually making up a scientific field (Seglen, 1992a).…”

Section: Distribution Of Article Citedness Within the Study Populationmentioning

confidence: 95%

Causal relationship between article citedness and journal impact

Seglen

1994

J. Am. Soc. Inf. Sci.

209

146

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The relationship between article citedness and journal impact was investigated on the basis of complete publication lists provided by 16 senior scientists from a major Norwegian biomedical research institute. The citedness of each individual journal article was measured as the mean annual number of citations during the second to fourth year after publication, and compared with the impact factor (mean article citedness) of each corresponding journal, recorded during the first two years after publication. The distribution of article citedness was very skewed (corresponding to a topnormal, extreme‐property distribution yielding linearity in a semilogarithmic plot), even for individual authors and within defined journal impact cohorts. The large variability was not due to random citation of the individual article, but rather to a fundamental heterogeneity among the articles. A similar skewness was found in the distribution of journal impact values, whereas the author impact distribution was less heterogeneous. The skewed distributions resulted in poor correlations between article citedness and journal impact, for the whole article population (correlation coefficient, c=0.41) as well as for individual authors (mean c=0.32; range 0.05–0.66) and journal pairs (mean c=0.22). Pooling of articles into defined journal impact cohorts dramatically improved the correlation (c=0.999 for the study group as a whole), indicating that the authors tended to submit their most cited work to journals of higher impact (although several notable exceptions were observed among individual authors). However, very large numbers of articles (50–100) had to be pooled in order to obtain good correlations (c=0.8–0.9). Furthermore, the mean citedness of the study group (3.34 ± 0.16 citations/article/year; mean ± SE of 907 articles) differed significantly from the corresponding mean journal impact (2.61 ± 0.07); for individual authors even larger discrepancies were observed. Use of journal impact as an evaluation parameter may therefore yield highly misleading results, unless the evaluated unit (author, research group, institution, or country) happens to be equal to the world average. By dividing the authors into a highly cited group (the eight most cited authors) and a less cited group (the eight least cited authors) it was possible to observe a twofold ratio in citedness between the two groups throughout the journal impact range. This difference could not be accounted for by journal choice, and did not diminish with increasing journal impact. The citedness of journal articles thus does not seem to be detectably influenced by the status of the journal in which they are published. © 1994 John Wiley & Sons, Inc.

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Section: Distribution Of Article Citedness Within the Study Populationmentioning

confidence: 95%

Causal relationship between article citedness and journal impact

Seglen

1994

J. Am. Soc. Inf. Sci.

209

146

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“…As far as the skewness of citation distributions is concerned, together with the illustrations in Seglen's paper from a random sample of articles drawn from the 1985-1989 Science Citation Index, and Magyar's (1973) data on the small sub-field of dye laser research, a first set of papers only includes the contributions of Irvine and Martin (1984) and Lehmann et al (2003) on high energy physics, and Burke and Butler (1996) on the entire fields of the natural sciences and the social sciences and the humanities in Australian universities. On the other hand, beyond the graphical illustrations included in Narayan (1971) and Seglen (1992), the only directly estimated results that we have found in the fitting of power laws to citation distributions are for papers on all fields published in 1981 and listed in the Science Citation Index (Redner, 1998, Clauset et al, 2009, papers published in Physical Review during long time periods (Redner, 1998(Redner, , 2005, 18,000 publications in Chemistry in the Netherlands during 1991-2000 with a three-year citation window (Van Raan, 2006), and papers in high energy physics (Lehmann et al, 2003(Lehmann et al, , 2008; Laherrère and Sornette (1998) study the citation record of the most cited physicists, while Clauset et al (2009) include the publication record of mathematicians.…”

Section: -2002 Acquired From Thomson Scientific (Ts Hereafter)mentioning

confidence: 99%

The skewness of science in 219 sub-fields and a number of aggregates

et al. 2011

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This paper studies evidence from Thomson Scientific about the citation process of 3.7 million articles published in the period 1998-2002 in 219 Web of Science categories, or sub-fields. Reference and citation distributions have very different characteristics across sub-fields. However, when analyzed with the Characteristic Scores and Scales technique, which is replication and scale invariant, the shape of these distributions over three broad categories of articles appears strikingly similar. Reference distributions are mildly skewed, but citation distributions with a five-year citation window are highly skewed: the mean is twenty points above the median, while 9-10% of all articles in the upper tail account for about 44% of all citations. The aggregation of sub-fields into disciplines and fields according to several aggregation schemes preserve this feature of citation distributions. It should be noted that when we look into subsets of articles within the lower and upper tails of citation distributions the universality partially breaks down. On the other hand, for 140 of the 219 sub-fields the existence of a power law cannot be rejected. However, contrary to what is generally believed, at the sub-field level the scaling parameter is above 3.5 most of the time, and power laws are relatively small: on average, they represent 2% of all articles and account for 13.5% of all citations. The results of the aggregation into disciplines and fields reveal that power law algebra is a subtle phenomenon.

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“…A simple example is the Relative Citation Rate of a group of articles (13), defined as the total number of citations they received, divided by the weighted sum of impact factors of the journals where the articles were published. The use of relative indicators is widespread, but empirical studies (19)(20)(21) have shown that distributions of article citations are very skewed, even within single disciplines. One may wonder then whether it is appropriate to normalize by the average citation number, which gives only very limited characterization of the whole distribution.…”

mentioning

confidence: 99%

Universality of citation distributions: Toward an objective measure of scientific impact

Radicchi

Fortunato

Castellano

2008

Proc. Natl. Acad. Sci. U.S.A.

710

676

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We study the distributions of citations received by a single publication within several disciplines, spanning broad areas of science. We show that the probability that an article is cited c times has large variations between different disciplines, but all distributions are rescaled on a universal curve when the relative indicator c f ‫؍‬ c/c 0 is considered, where c0 is the average number of citations per article for the discipline. In addition we show that the same universal behavior occurs when citation distributions of articles published in the same field, but in different years, are compared. These findings provide a strong validation of c f as an unbiased indicator for citation performance across disciplines and years. Based on this indicator, we introduce a generalization of the h index suitable for comparing scientists working in different fields.bibliometrics ͉ analysis ͉ h index

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Power Law Relations in Science Bibliography—a Self‐consistent Interpretation

Cited by 68 publications

References 13 publications

Causal relationship between article citedness and journal impact

Causal relationship between article citedness and journal impact

The skewness of science in 219 sub-fields and a number of aggregates

Universality of citation distributions: Toward an objective measure of scientific impact

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