Search Results
Abstract
I studied the distribution of changes in journal impact factors (JIF) between 1998 and 2007 according to an empirical beta law with two exponents. Changes in JIFs (CJIF) were calculated as the quotient obtained by dividing the JIF for a given year by the JIF for the preceding year. The CJIFs showed good fit to a beta function with two exponents. In addition, I studied the distribution of the changes in segments of the CJIF rank order. The distributions, which were similar from year to year, could be fitted to a Lorentzian function. The methods used here can be useful to understand the changes in JIFs using relatively simple functions.
Abstract
A scheme of evaluating an impact of a given scientific paper based on importance of papers quoting it is investigated. Introducing a weight of a given citation, dependent on the previous scientific achievements of the author of the citing paper, we define the weighting factor of a given scientist. Technically the weighting factors are defined by the components of the normalized leading eigenvector of the matrix describing the citation graph. The weighting factor of a given scientist, reflecting the scientific output of other researchers quoting his work, allows us to define weighted number of citation of a given paper, weighted impact factor of a journal and weighted Hirsch index of an individual scientist or of an entire scientific institution.
Abstract
This paper examines the genesis of journal impact measures and how their evolution culminated in the journal impact factor (JIF) produced by the Institute for Scientific Information. The paper shows how the various building blocks of the dominant JIF (published in the Journal Citation Report - JCR) came into being. The paper argues that these building blocks were all constructed fairly arbitrarily or for different purposes than those that govern the contemporary use of the JIF. The results are a faulty method, widely open to manipulation by journal editors and misuse by uncritical parties. The discussion examines some solution offered to the bibliometrics and scientific communities considering the wide use of this indicator at present.
Abstract
The assessment of the publications of research teams working on different subfields raises concerns because of the different scientometric features of the subfields. For equalizing the differences in the Garfield (Impact) Factors of journals, several methods applied in practice have been described. A new indicator – Specific Impact Contribution (SIC) relating the citation share of a respective team (or journal) in the total citations of the teams (or journals) evaluated to its share in publications – was introduced. It has been realized that the normalized Garfield Factors and the normalized SIC values are identical measures within any selected set of journals. Consequently, the Garfield Factor of a journal should be assumed as an indicator characterizing the contribution of the information channel as a whole, appropriately.
Abstract
Owing to some discussions about manipulating impact factor by requesting authors to increase their citations to the publication journal, we theoretically establish a mathematical expression of a relation between the journal self-citation rate and its impact factor by the single-factor method in this paper. Based on self-citation data of some journals in JCR and the observed relation between journal impact factor and the self-cited rate, we analyze the possibility that journal editors manipulate impact factors of their journals by raising the self-cited rate. Finally, we make some suggestions for supervising this crude way of active manipulating the impact factor.
Summary
The inter-citation journal group is defined as a group of journals with inter-citation relations. In this paper, according to the 2003 JCR, an inter-citation relation matrix of 10 medical journals is established. Based on the transfer function model of the disturbed citing process, the calculation formula of journal impact factor disturbed by publication delays of certain journal in the group is deduced and a changing process of every journal's impact factor caused by the increase of each journal's average publication delay is simulated. In the inter-citation journal group, when a journal's publication delay increase, impact factors of all journals will be decreased and rankings of journals according to the impact factor may be changed. The closer a citation relation between two journals, the stronger the interaction of them and the larger the decrease of their impact factors caused by the increase of their publication delays.
Abstract
It is shown that the Journal Impact Factor as published by ISI — an indicator increasingly used as an measure for the quality of scientific journals — is misleading when two leading journals in chemistry,Angew. Chem., andJ. Am. Chem. Soc., are compared. A detailed analysis of the various kinds publications in both journals over the period 1982–1994 shows that the overall impact factors based on publications and citations in two consecutive years forJACS communications (5.27 for 1993) are significantly higher than those ofAngew. Chem. (3.26 for 1993). Even when all types of articles, i.e. including reviews, are included in the impact factors,JACS has a higher score thanAngew. Chem. (5.07 vs. 4.03 in 1993). Critical and accurate analyses of citation figures is required when such data are used in science policy decisions, such as library subscriptions. It is proposed that when IF values for several journals are compared, only similar publication types are considered.
Abstract
Impact factor is a quasi-qualitative indicator, which provides a measurement of the prestige and international visibility of journals. Although the use of impact factor-based indicators for science policy purposes has increased over the last two decades, several limitations have been pointed out and should be borne in mind. The use of impact factor should be treated carefully when applied to the analysis of peripheral countries, whose national journals are hardly covered by ISI databases. Our experience in the use of impact factor based indicators for the analysis of the Spanish scientific production is shown. The usefulness of the impact factor measures in macro, meso and micro analyses is displayed. In addition, the main advantages, such as the great accessibility of impact factor and its ready-to-use nature are pointed out. Several limitations such as the need to avoid inter-field comparisons or the convenience of using a fixed journal set for international comparisons are also stressed. It is worth noting that the use of impact factor in the research evaluation process has influenced strongly the publication strategy of scientists.
Summary
This paper discusses the relationship between Journal Impact Factors and the scientific community's judgment of the quality of journals in regional science, a discipline closely related to economics and geography. The paper compares the results of a survey inquiring the quality of journals in the discipline with the impact factors of these journals for a total of five years. The comparison shows that no significant positive correlation between the impact factors and the peer judgments can be found. In many cases the correlation turns out to be negative - in some cases even significantly.
Abstract
The standard impact factor for particular fields of science (Ig) and the relative impact factor K for scientific journals are introduced. The technique of calculation of standard impact factor (Ig) for a field is an inherent part of a method which allows a cross-field evaluation of scientific journals. This method for evaluating scientific journals elaborated in 1988 was aimed at the analysis of Russian journals covered by the SCI database, it was also used for chemical journals (more that 300) and for journals in the Life sciences (more than 1000). The results are discussed.
