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  • Author or Editor: Thed van Leeuwen x
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Abstract

In this study the issue of the validity of the argument against the applied length of citation windows in Journal Impact Factors calculations is critically re-analyzed. While previous studies argued against the relatively short citation window of 1–2 years, this study shows that the relative short term citation impact measured in the window underlying the Journal Impact Factor is a good predictor of the citation impact of the journals in the next years to come. Possible exceptions to this observation relate to journals with relatively low numbers of publications, and the citation impact related to publications in the year of publication. The study focuses on five Journal Subject Categories from the science and social sciences, on normal articles published in these journals, in the 2 years 2000 and 2004.

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Summary  

The paper discusses an application of bibliometric techniques in the social sciences. While the interest of policy makers is growing, the topic is getting more and more attention from bibliometricians. However, many efforts are put into developing tools to measure scientific output and impact outside the world of the Social Sciences Citation Index, while the use of the SSCI for bibliometric applications is covered with obscurity and myths. This study attempts to clarify some of the topics mentioned against the application of the SSCI for evaluation purposes. The study will cover topics like the existing publication and citation culture within the social sciences, the effect of variable citation windows, and the (geographical) origin of citation flows.

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Abstract  

In this study we have focused on long term developments of various types of scientific publishing, and the field-normalized impact generated by these various types. The types of scientific output distinguished are output resulting from international cooperation, national cooperation, and single address publications, in which no apparent cooperation is found. A fourth type is distinguished by focusing on first authorship, within the international cooperation output. Changes in especially the share of a country’s output from first-authored international cooperation and the share of single address publications can be regarded as indicators of strength and/or weakness of a science system.

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Abstract  

This paper discusses development and application of journal impact indicators in a number of bibliometric studies commissioned by Dutch organizations and institutions, and conducted in our institute during the past five years. An outline is given of the research questions addressed in these studies and their policy context. For each study the appropriateness of the use of journal impact indicators produced by the Institute for Scientific Information (ISI) is evaluated. Alternative journal impact measures were developed which are shown to be more appropriate in the particular research and policy contexts than the ISI measures. These measures were considered to be highly useful by the users. The studies have revealed methodological flaws of the ISI journal impact factors.

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Abstract  

This paper focuses on the study of self-citations at the meso and micro (individual) levels, on the basis of an analysis of the production (1994–2004) of individual researchers working at the Spanish CSIC in the areas of Biology and Biomedicine and Material Sciences. Two different types of self-citations are described: author self-citations (citations received from the author him/herself) and co-author self-citations (citations received from the researchers’ co-authors but without his/her participation). Self-citations do not play a decisive role in the high citation scores of documents either at the individual or at the meso level, which are mainly due to external citations. At micro-level, the percentage of self-citations does not change by professional rank or age, but differences in the relative weight of author and co-author self-citations have been found. The percentage of co-author self-citations tends to decrease with age and professional rank while the percentage of author self-citations shows the opposite trend. Suppressing author self-citations from citation counts to prevent overblown self-citation practices may result in a higher reduction of citation numbers of old scientists and, particularly, of those in the highest categories. Author and co-author self-citations provide valuable information on the scientific communication process, but external citations are the most relevant for evaluative purposes. As a final recommendation, studies considering self-citations at the individual level should make clear whether author or total self-citations are used as these can affect researchers differently.

Open access

Abstract  

Bio-pharmaceutical R&D is increasingly an international affair. Research articles published in the peer-reviewed international scientific and technical journals represent quantifiable research outputs of bio-pharmaceutical firms. Large-scale systemic measurements of worldwide trends and sectoral patterns within bio-pharmaceutical science can be gauged from these articles, where coauthored research papers are assumed to reflect research cooperation and associated knowledge flows and exchanges. We focus our attention on the largest science-based multinational enterprises (MNEs), those that produce relatively large quantities of research articles. The study deals with the worldwide output of research articles that are co-produced by corporate researchers during the years 1996–2001. We employ these publications to examine structural factors characterizing research cooperation networks within industry at the level of major geographical regions (North America, Europe, Pacific-Asia), with a breakdown by within-MNE and between-MNE network linkages. The descriptive statistics on publication output and results of network analyses of co-publication linkages not only indicate regional differences, with a central role for US companies in biopharmaceutical research, but also a variety of firm-specific research cooperation networks which enabled us to develop a tentative typology of MNEs in terms of their intra- and interorganizational patterns of research cooperation linkages.

Open access

Abstract  

This paper introduces a citation-based "systems approach" for analyzing the various institutional and cognitive dimensions of scientific excellence within national research systems. The methodology, covering several aggregate levels, focuses on the most highly cited research papers in the international journal literature. The distribution of these papers across institutions and disciplines enables objective comparisons their (possible) international-level scientific excellence. By way of example, we present key results from a recent series of analyses of the research system in the Netherlands in the mid 1990s, focussing on the performance of the universities across the various major scientific disciplines within the context of the entire system"s scientific performance. Special attention is paid to the contribution in the world"s top 1% and top 10% most highly cited research papers. The findings indicate that these high performance papers provide a useful analytical framework - both in terms of transparency, cognitive and institutional differentiation, as well as its scope for domestic and international comparisons - providing new indicators for identifying "world class" scientific excellence at the aggregate level. The average citation scores of these academic "Centres of Scientific Excellence" appear to be an inadequate predictor of their production of highly cited papers. However, further critical reflection and in-depth validation studies are needed to establish the true potential of this approach for science policy analyses and evaluation of research performance.

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Summary In this study, journal impact factors play a central role. In addition to this important bibliometric indicator, which evolves around the average impact of a journal in a two-year timeframe, related aspects of journal impact measurement are studied. Aspects like the output volume, the percentage of publications not cited, and the citation frequency distribution within a set timeframe are researched, and put in perspective with the 'classical' journal Impact Factor. In this study it is shown that these aspects of journal impact measurement play a significant role, and are strongly inter-related. Especially the separation between journals on the basis of the differences in output volume seems to be relevant, as can be concluded from the different results in the analysis of journal impact factors, the degree of uncitedness, and the share of a journal its contents above or below the impact factor value.

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Abstract  

In this study we show that it is possible to identify top-cited publications other than Web of Science (WoS) publications, particularly non-journal publications, within fields in the social and behavioral sciences. We analyzed references in publications that were themselves highly cited, with at least one European address. Books represent between 62 (psychology) and 81% (political science) of the non-WoS references, journal articles 15–24%. Books (economics, political science) and manuals (psychology) account for the most highly cited publications. Between 50 (psychology, political science) and 71% (economics) of the top-ranked most cited publications originated from the US versus between 18 (economics) and 38% (psychology) from Europe. Finally, it is discussed how the methods and procedures of the study can be optimized.

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Abstract  

In an evaluation of physics research programs in the Netherlands, held in 1996, assessments of research by expert panels were supplemented with bibliometric analysis. This latter analysis included the calculation of several bibliometric indicators, among which some taking journal impact measures as a baseline. Final outcomes of this evaluation provided an opportunity to re-examine the results of this assessment from the perspective of the degree of interdisciplinarity of programs involved. In this paper we discuss results of this latter analysis, in particular with respect to the relation between several citation based indicators and interdisciplinary research in Dutch physics.

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