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  • × author_ss:"Leydesdorff, L."
  1. Leydesdorff, L.; Bornmann, L.; Mutz, R.; Opthof, T.: Turning the tables on citation analysis one more time : principles for comparing sets of documents (2011) 0.02
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    Abstract
    We submit newly developed citation impact indicators based not on arithmetic averages of citations but on percentile ranks. Citation distributions are-as a rule-highly skewed and should not be arithmetically averaged. With percentile ranks, the citation score of each paper is rated in terms of its percentile in the citation distribution. The percentile ranks approach allows for the formulation of a more abstract indicator scheme that can be used to organize and/or schematize different impact indicators according to three degrees of freedom: the selection of the reference sets, the evaluation criteria, and the choice of whether or not to define the publication sets as independent. Bibliometric data of seven principal investigators (PIs) of the Academic Medical Center of the University of Amsterdam are used as an exemplary dataset. We demonstrate that the proposed family indicators [R(6), R(100), R(6, k), R(100, k)] are an improvement on averages-based indicators because one can account for the shape of the distributions of citations over papers.
    Source
    Journal of the American Society for Information Science and Technology. 62(2011) no.7, S.1370-1381
  2. Leydesdorff, L.: ¬The construction and globalization of the knowledge base in inter-human communication systems (2003) 0.01
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    Date
    22. 5.2003 19:48:04
    Source
    Canadian Journal of Communication 28(2003), H.3, S. -
  3. Leydesdorff, L.: Can networks of journal-journal citations be used as indicators of change in the social sciences? (2003) 0.01
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    Date
    6.11.2005 19:02:22
    Source
    Journal of documentation. 59(2003) no.1, S.84-104
  4. Leydesdorff, L.; Sun, Y.: National and international dimensions of the Triple Helix in Japan : university-industry-government versus international coauthorship relations (2009) 0.01
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    Date
    22. 3.2009 19:07:20
    Source
    Journal of the American Society for Information Science and Technology. 60(2009) no.4, S.778-788
  5. Leydesdorff, L.; Bornmann, L.; Wagner, C.S.: ¬The relative influences of government funding and international collaboration on citation impact (2019) 0.01
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    Date
    8. 1.2019 18:22:45
    Source
    Journal of the Association for Information Science and Technology. 70(2019) no.2, S.198-201
  6. Leydesdorff, L.; Bornmann, L.: How fractional counting of citations affects the impact factor : normalization in terms of differences in citation potentials among fields of science (2011) 0.01
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    Date
    22. 1.2011 12:51:07
    Source
    Journal of the American Society for Information Science and Technology. 62(2011) no.2, S.217-229
  7. Hellsten, I.; Leydesdorff, L.: ¬The construction of interdisciplinarity : the development of the knowledge base and programmatic focus of the journal Climatic Change, 1977-2013 (2016) 0.01
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    Date
    24. 8.2016 17:53:22
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.9, S.2181-2193
  8. Leydesdorff, L.; Johnson, M.W.; Ivanova, I.: Toward a calculus of redundancy : signification, codification, and anticipation in cultural evolution (2018) 0.01
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    Date
    29. 9.2018 11:22:09
    Source
    Journal of the Association for Information Science and Technology. 69(2018) no.10, S.1181-1192
  9. Leydesdorff, L.: Should co-occurrence data be normalized : a rejoinder (2007) 0.00
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    Source
    Journal of the American Society for Information Science and Technology. 58(2007) no.14, S.2411-2413
  10. Leydesdorff, L.: Accounting for the uncertainty in the evaluation of percentile ranks (2012) 0.00
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    Source
    Journal of the American Society for Information Science and Technology. 63(2012) no.11, S.2349-2350
  11. Bornmann, L.; Leydesdorff, L.: Statistical tests and research assessments : a comment on Schneider (2012) (2013) 0.00
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    Source
    Journal of the American Society for Information Science and Technology. 64(2013) no.6, S.1306-1308
  12. Leydesdorff, L.; Wagner, C,; Bornmann, L.: Replicability and the public/private divide (2016) 0.00
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    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.7, S.1777-1778
  13. Leydesdorff, L.: ¬A sociological theory of communication : the self-organization of the knowledge-based society (2001) 0.00
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    Footnote
    Rez. in: JASIST 53(2002) no.1, S.61-62 (E.G. Ackermann): "This brief summary cannot do justice to the intellectual depth, philosophical richness of the theoretical models, and their implications presented by Leydesdorff in his book. Next to this, the caveats presented earlier in this review are relatively minor. For all that, this book is not an "easy" read, nor is it for the theoretically or philosophically faint of heart. The content is certainly accessible to those with the interest and the stamina to see it through to the end, and would repay those who reread it with further insight and understanding. This book is recommended especially for the reader who is looking for a well-developed, general sociological theory of communication with a strong philosophical basis upon which to build a postmodern, deconstructionist research methodology"
    Pages
    351 S
  14. Leydesdorff, L.; Bensman, S.: Classification and Powerlaws : the logarithmic transformation (2006) 0.00
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    Source
    Journal of the American Society for Information Science and Technology. 57(2006) no.11, S.1470-1486
  15. Leydesdorff, L.; Strand, Oe.: ¬The Swedish system of innovation : regional synergies in a knowledge-based economy (2013) 0.00
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    Location
    S
    Source
    Journal of the American Society for Information Science and Technology. 64(2013) no.9, S.1890-1902
  16. Leydesdorff, L.; Heimeriks, G.; Rotolo, D.: Journal portfolio analysis for countries, cities, and organizations : maps and comparisons (2016) 0.00
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    Abstract
    Using Web of Science data, portfolio analysis in terms of journal coverage can be projected onto a base map for units of analysis such as countries, cities, universities, and firms. The units of analysis under study can be compared statistically across the 10,000+ journals. The interdisciplinarity of the portfolios is measured using Rao-Stirling diversity or Zhang et?al.'s improved measure 2D3. At the country level we find regional differentiation (e.g., Latin American or Asian countries), but also a major divide between advanced and less-developed countries. Israel and Israeli cities outperform other nations and cities in terms of diversity. Universities appear to be specifically related to firms when a number of these units are exploratively compared. The instrument is relatively simple and straightforward, and one can generalize the application to any document set retrieved from the Web of Science (WoS). Further instruction is provided online at http://www.leydesdorff.net/portfolio.
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.3, S.741-748
  17. Zhou, Q.; Leydesdorff, L.: ¬The normalization of occurrence and co-occurrence matrices in bibliometrics using Cosine similarities and Ochiai coefficients (2016) 0.00
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    Abstract
    We prove that Ochiai similarity of the co-occurrence matrix is equal to cosine similarity in the underlying occurrence matrix. Neither the cosine nor the Pearson correlation should be used for the normalization of co-occurrence matrices because the similarity is then normalized twice, and therefore overestimated; the Ochiai coefficient can be used instead. Results are shown using a small matrix (5 cases, 4 variables) for didactic reasons, and also Ahlgren et?al.'s (2003) co-occurrence matrix of 24 authors in library and information sciences. The overestimation is shown numerically and will be illustrated using multidimensional scaling and cluster dendograms. If the occurrence matrix is not available (such as in internet research or author cocitation analysis) using Ochiai for the normalization is preferable to using the cosine.
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.11, S.2805-2814
  18. Leydesdorff, L.; Heimeriks, G.: ¬The self-organization of the European information society : the case of "biotechnology" (2001) 0.00
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    Footnote
    Vgl. auch die Stellungnahme von P. van den Besselaar: Empirical evidence of self-organization? in: JASIST 54(2003) no.1, S.87-90.
    Source
    Journal of the American Society for Information Science and technology. 52(2001) no.14, S.1262-1274
  19. Leydesdorff, L.: ¬The generation of aggregated journal-journal citation maps on the basis of the CD-ROM version of the Science Citation Index (1994) 0.00
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    Source
    Scientometrics. 31(1994) no.1, S.59-84
  20. Leydesdorff, L.: Theories of citation? (1999) 0.00
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    Source
    Scientometrics. 43(1998) no.1, S.5-25