Betweenness and diversity in journal citation networks as measures of interdisciplinarity—A tribute to Eugene Garfield

Authors : Loet Leydesdorff, Caroline S. Wagner, Lutz Bornmann

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.

URL : Betweenness and diversity in journal citation networks as measures of interdisciplinarity—A tribute to Eugene Garfield




To what extent does the Leiden Manifesto also apply to altmetrics? A discussion of the manifesto against the background of research into altmetrics

Authors : Lutz Bornmann, Robin Haunschild


Hicks, Wouters, Waltman, de Rijcke, and Rafols (2015) have formulated the so-called Leiden manifesto, in which they have assembled the ten principles for a meaningful evaluation of research on the basis of bibliometric data.


In this work the attempt is made to indicate the relevance of the Leiden manifesto for altmetrics.


As shown by the discussion of the ten principles against the background of the knowledge about and the research into altmetrics, the principles also have a great importance for altmetrics and should be taken into account in their application.


Altmetrics is already frequently used in the area of research evaluation. Thus, it is important that the user of altmetrics data knows the relevance of the Leiden manifesto also in this area.