Information about the CWTS Leiden Ranking

The CWTS Leiden Ranking is an online platform that offers important insights into the scientific performance of over 1500 major universities worldwide. Below we provide some general information about the Leiden Ranking.

Why do you produce the Leiden Ranking?

Our aim in producing the Leiden Ranking is twofold:

  1. We aim to provide a service to the scientific community by making available high-quality information on the scientific performance of universities and by offering an alternative to other well-known university rankings, such as the Times Higher Education World University Rankings, the QS World University Rankings, and the Academic Ranking of World Universities, which we believe to provide questionable information.
  2. We aim to provide a demonstration of state-of-the-art bibliometric methods and of the information that CWTS is able to offer using such methods.

For whom do you produce the Leiden Ranking?

We produce the Leiden Ranking for policy makers, research managers, researchers, journalists, and anyone else with an interest in the scientific performance of universities. The Leiden Ranking does not consider the performance of universities in terms of teaching. We therefore expect the information provided by the Leiden Ranking to be of little value for students, and we advise students not to use the Leiden Ranking to choose where to study.

How do you obtain the data on which the Leiden Ranking is based?

The Leiden Ranking is based on bibliographic data on scientific publications, in particular on articles published in scientific journals. As discussed in more detail here, we currently use Web of Science as our primary data source. CWTS has a special Web of Science license that enables us to use Web of Science data to produce the Leiden Ranking. Data from Web of Science is enriched by CWTS in various ways. In particular, as discussed here, we take a very careful approach to identify the publications of a university. For the open access indicators in the Leiden Ranking, we use data from OpenAlex. The Leiden Ranking does not use any data obtained directly from universities.

How do you select the universities included in the Leiden Ranking?

We aim to include as many universities as possible in the Leiden Ranking, but we do not have the resources to comprehensively cover all universities worldwide. A university therefore needs to have a certain minimum number of scientific publications in order to be included in the Leiden Ranking. This is discussed in more detail here.

How does the Leiden Ranking differ from other university rankings?

The Leiden Ranking offers a responsible approach to university ranking. We recognize that universities are complex organizations that have a variety of forms, contexts, and missions, which means that representing the performance of a university in a single number does not make sense. Unlike other well-known university rankings, the Leiden Ranking therefore presents a variety of indicators, enabling the performance of universities to be explored from a diversity of perspectives.
The exclusive focus on the scientific performance of universities also distinguishes the Leiden Ranking from other university rankings. Other aspects of the performance of universities, in particular their contribution to teaching, are not considered in the Leiden Ranking. Unlike other university rankings, the Leiden Ranking is based entirely on bibliographic data on scientific publications. It relies on a sophisticated approach to data collection and provides a set of advanced bibliometric indicators.

How is the Leiden Ranking funded?

Most of the funding for the Leiden Ranking is currently provided by U-Multirank and the European Research Infrastructure for Science, technology and Innovation policy Studies (RISIS). The Leiden Ranking is also partly self-funded by CWTS.

UMultiRank RISIS2

Do you have any competing interests?

Through CWTS B.V., a company affiliated with the CWTS research center and owned by Leiden University, we offer services for research evaluation and strategic decision making to universities and other research organizations. As part of this, we provide organizations with bibliometric indicators similar to those made available in the Leiden Ranking. Revenues generated through CWTS B.V. are used to sustain and strengthen the work of the CWTS research center.

What are your future plans for the Leiden Ranking?

We are currently exploring the possibility of creating an open edition of the Leiden Ranking that is fully transparent and reproducible. More information about this ongoing project can be found in this blog post.