Leydesdorff Loet, Wagner Caroline S, Bornmann Lutz
1Amsterdam School of Communication Research (ASCoR), University of Amsterdam, PO Box 15793, 1001 NG Amsterdam, The Netherlands.
2John Glenn College of Public Affairs, The Ohio State University, Columbus, OH 43210 USA.
Scientometrics. 2018;114(2):567-592. doi: 10.1007/s11192-017-2528-2. Epub 2017 Oct 4.
Journals were central to Eugene Garfield's research interests. Among other things, journals are considered as units of analysis for bibliographic databases such as the Web of Science and Scopus. In addition to providing a basis for disciplinary classifications of journals, journal citation patterns span networks across boundaries to variable extents. Using betweenness centrality (BC) and diversity, we elaborate on the question of how to distinguish and rank journals in terms of interdisciplinarity. Interdisciplinarity, however, is difficult to operationalize in the absence of an operational definition of disciplines; the diversity of a unit of analysis is sample-dependent. BC can be considered as a measure of multi-disciplinarity. Diversity of co-citation in a citing document has been considered as an indicator of knowledge integration, but an author can also generate trans-disciplinary-that is, non-disciplined-variation by citing sources from other disciplines. Diversity in the bibliographic coupling among citing documents can analogously be considered as diffusion or differentiation of knowledge across disciplines. Because the citation networks in the cited direction reflect both structure and variation, diversity in this direction is perhaps the best available measure of interdisciplinarity at the journal level. Furthermore, diversity is based on a summation and can therefore be decomposed; differences among (sub)sets can be tested for statistical significance. In the appendix, a general-purpose routine for measuring diversity in networks is provided.
期刊是尤金·加菲尔德研究兴趣的核心。除其他方面外，期刊被视为诸如《科学引文索引》和《Scopus》等文献数据库的分析单元。除了为期刊的学科分类提供基础外，期刊的引用模式在不同程度上跨越边界形成网络。我们运用中介中心性（BC）和多样性，阐述了如何根据跨学科性来区分期刊并对其进行排名的问题。然而，在缺乏学科的操作性定义的情况下，跨学科性很难实施；分析单元的多样性取决于样本。BC可以被视为一种多学科性的度量。被引文献中共引的多样性被视为知识整合的一个指标，但作者也可以通过引用其他学科的文献来源产生跨学科——即无学科限制的——变化。类似地，被引文献之间文献耦合的多样性可以被视为知识在各学科间的传播或分化。因为被引方向上的引用网络既反映了结构又反映了变化，所以这个方向上的多样性可能是期刊层面跨学科性的最佳可用度量。此外，多样性基于求和，因此可以分解；（子）集之间的差异可以进行统计显著性检验。附录中提供了一个用于测量网络多样性的通用程序。
