The CWTS Leiden Ranking 2025 - More open, more inclusive, more informative The release of the CWTS Leiden Ranking 2025 marks a next step toward more open and more inclusive research analytics for universities. This post highlights the most significant developments. Nees Jan van Eck, Rodrigo Costas, Mark Neijssel, Ed Noyons, Martijn Visser and Ludo Waltman • October 29, 2025
Crossref as a source of open bibliographic metadata for preprints Crossref is a crucial source of open bibliographic metadata for articles published in scientific journals. Importantly, however, Crossref can also serve as a source of bibliographic metadata for preprints. In this post, Van Eck and Waltman analyze the completeness of Crossref’s preprint metadata. Nees Jan van Eck and Ludo Waltman • October 16, 2025
Making bibliometric reporting more transparent and consistent: Participants needed for pilot testing of GLOBAL The team behind the GLOBAL reporting guideline invites researchers who are preparing or reviewing a bibliometric article to take part in a pilot test of the guideline. Jeremy Y. Ng, Dimity Stephen, David Moher, Ludo Waltman and Stefanie Haustein • August 12, 2025
The state of preprinting in Europe and the Netherlands To accelerate the sharing of scientific knowledge, researchers in many disciplines increasingly publish their work on preprint servers. In this post, Ludo Waltman and colleagues discuss the state of preprinting in Europe and the Netherlands. Ludo Waltman, Narmin Rzayeva and Stephen Pinfield • May 22, 2025 • 1 comment
Advancing our Understanding of Systematic Manipulation & Paper Mills: Wiley & CWTS Partnership The Centre for Science and Technology Studies at Leiden University, in collaboration with the publishing company Wiley, is opening a new position for a PhD candidate to carry out research on paper mills and related forms of systematic manipulation in publishing. Wolfgang Kaltenbrunner, Catriona J Maccallum, Stephen Pinfield, Mike Streeter and Ludo Waltman • April 15, 2025
Assessment reform and publishing reform need to go hand in hand The need to reform research assessment and scientific publishing practices is widely recognized. However, Ludo Waltman argues that the assessment and publishing reform movements will be successful only if they manage to align their agendas. Ludo Waltman • March 26, 2025
Shaping the Future of Open Research Information - Reflections from the National Open Science Festival At the National Open Science Festival, we explored challenges in implementing the Barcelona Declaration, including vendor lock-in, data quality, cultural resistance and advocacy gaps. Participants brainstormed actionable solutions, highlighting collaboration, training and outreach as key drivers. Ana Ranitovic, Jeroen Bosman and Ludo Waltman • December 18, 2024
Opening the black box of university rankings Today two university rankings were released, one by CWTS and one by Times Higher Education. Ludo Waltman and Nees Jan van Eck, responsible for the CWTS Leiden Ranking, use this occasion to discuss the importance of transparency of rankings. Ludo Waltman and Nees Jan van Eck • October 09, 2024
Launch of the CWTS Leiden Ranking Open Edition 2024 Earlier this year CWTS published the first Open Edition of the CWTS Leiden Ranking. Today the Leiden Ranking Open Edition 2024 was launched. In this post, Nees Jan van Eck and colleagues discuss the latest developments around the Open Edition of the Leiden Ranking. Nees Jan van Eck, Ludo Waltman and Mark Neijssel • October 09, 2024
