Interdisciplinary research figures high on today's policy agendas. This short introduction
and overview sketches the complexity of defining and mapping the nature of interdisciplinary
research (IDR). The paper focuses on the different approaches to IDR and different
methods applied in bibliometric studies that allow measuring it. These methods should
not only be able to capture quantitative aspects of IDR but also to monitor evolutionary
aspects and help answer the question of whether IDR stimulates collaboration and results
in larger impact and visibility. Two specific indicators, variety and disparity, are
developed, validated and applied to bibliometric data. They enable the visualization
of the interdisciplinary nature of research activities at various levels of analysis
(both institutional and individual). And, given the longitudinal character of bibliometric
data and databases, both indicators allow for mapping time-dependent phenomena and
evolutions. Relevant examples based on the literature and recent results from research
conducted at the Leuven bibliometrics group of ECOOM (e.g., Glanzel et al., Proceedings
of the 18(th) International Conference of the International Society of Scientometrics
and Informetrics, 453-464, 2021; Huang et al., Proceedings of the 18(th) International
Conference of the International Society of Scientometrics and Informetrics, 533-538,
2021) are given, and concrete proposals for future research are articulated.
