شاخص گذاری بین ضریب تاثیر و استنادات

The Impact Factor has become a well-known measure of the average citation number of articles published in a scientific journal. A journal with a high Impact Factor is assumed to have a low percentage of uncited articles. We show that the scaling relation between the Impact Factor and the uncited percentage can be understood by a simple mechanism. The empirical data can be reproduced by a random mechanism with the cumulative advantage. To further explore the robustness of such a mechanism, we investigate the relation between the average citation number and the uncited percentage from different perspectives. We apply the idea of Impact Factor to the publications of an institute in addition to its general application to the publications of a journal. We find that the same scaling relation can be obtained. We also show that a static relation can be applied to describe the time evolution of a dynamical process. These results provide further justification for the same citation mechanism behind different research fields.

With the flourishing of scientific publications, citation dynamics has become an interesting topic of statistical physics. The rapid accumulation of scientific knowledge has made researchers more aware of where to best publish their research results. The Impact Factor (IF) has been a well-known measure of the citation impact of a science (or social science) journal [1]. Basically, the IF can be taken as the average number of citations to an article recently published in that journal. Specifically, the IF of a journal in a given year is the average number of citations to those articles that were published during the two preceding years. With a wide variety of scientific publications, a wide range of IFs can be expected. Although it is often taken as a direct measure of the quality of a journal, an IF also reflects the popularity of a subject. For example, a journal on biosciences often has a higher IF than a journal on mathematics. Although each journal has its own specialty, and the rankings of journals are quite stable over the years [2] and [3], there are still wide fluctuations in citation numbers for different articles published in the same journal [4]. Since citation counts are not evenly distributed, an IF calculated by the arithmetic mean is not sufficiently representative of an individual article. The use of a journal’s IF to evaluate the citation impact of an article within that journal can be controversial [5] and [6]. With the advance of statistical physics in the so-called field of sociophysics, various topics have been investigated to reveal the underlying mechanism in citation dynamics. The issue of uncitedness has been raised recently [7]. Intuitively, a journal with a high IF should have a low percentage of uncited articles. An interesting scaling relation in citation dynamics has been revealed [8]. When the average citation number is plotted against the uncited percentage, data from different journals collapse onto a single curve. Obviously the average citation number decreases with the increase of the uncited percentage. Yet the curve changes from a convex decrease to a concave decrease. There have been many discussions on the mathematical formulation of such a peculiar shape [9], [10] and [11]. To our knowledge, the underlying mechanism remains unexplored. In statistical physics, scaling of different datasets often indicates a general mechanism behind the process [12] and [13]. In this work, we show that the scaling curve can be understood by a simple mechanism. The scaling relation implies that the same mechanism works behind a wide variety of citation practices in scientific publications. Such a scaling curve can be used to differentiate among different mechanisms in citation dynamics. To further explore the robust mechanism of citation dynamics, we study the relation between the average citation number and the uncited percentage from different perspectives. Originally, the idea of IF was applied to the publications of a journal. In this study, we apply the idea of IF to the publications of an institute. In contrast to the uniformity among the many articles collected in a journal, the publication list of an institute consists of many articles from a wide range of scientific topics. Yet we find that the same scaling relation can still be discerned. We also observe that the static relation can be applied to describe the temporal evolution in the dynamical process of citation accumulation. In previous studies, the scaling relation has been portrayed as a static relation for many journals. As in the many cases of equilibrium statistical mechanics, a dynamic relation might become a static relation in the ensemble. These observations can provide further justification for the same mechanism behind different research fields.