The measurement of “interdisciplinarity” and “synergy” in scientific and extra‐scientific collaborations

Authors : Loet Leydesdorff, Inga Ivanova

Problem solving often requires crossing boundaries, such as those between disciplines. When policy‐makers call for “interdisciplinarity,” however, they often mean “synergy.” Synergy is generated when the whole offers more possibilities than the sum of its parts. An increase in the number of options above the sum of the options in subsets can be measured as redundancy; that is, the number of not‐yet‐realized options.

The number of options available to an innovation system for realization can be as decisive for the system’s survival as the historically already‐realized innovations. Unlike “interdisciplinarity,” “synergy” can also be generated in sectorial or geographical collaborations. The measurement of “synergy,” however, requires a methodology different from the measurement of “interdisciplinarity.”

In this study, we discuss recent advances in the operationalization and measurement of “interdisciplinarity,” and propose a methodology for measuring “synergy” based on information theory.

The sharing of meanings attributed to information from different perspectives can increase redundancy. Increasing redundancy reduces the relative uncertainty, for example, in niches.

The operationalization of the two concepts—“interdisciplinarity” and “synergy”—as different and partly overlapping indicators allows for distinguishing between the effects and the effectiveness of science‐policy interventions in research priorities.

URL : The measurement of “interdisciplinarity” and “synergy” in scientific and extra‐scientific collaborations

DOI : https://doi.org/10.1002/asi.24416

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

DOI : https://doi.org/10.1007/s11192-017-2528-2