The CWTS Leiden University Ranking for 2021 has been published by the Centre for Science and Technology Studies, Leiden University, The Netherlands. The Leiden Ranking is based on bibliographic data from the Web of Science database by Clarivate Analytics. It provides a rating that is based on the absolute number of top-cited publications (which is size-dependent), as well as a size-independent list, where the performance of a university’s publications is measured relative to its publication output. The 2021 list includes 1,225 universities in 69 different countries. Four new countries have been included this year: Ethiopia, Morocco, Nigeria, and Vietnam.

Just like last year, the top 20—based on the absolute number of publications that belong to the top 1 % most cited—consists mostly of institutions in the United States and the United Kingdom, in addition to one Canadian and one Chinese university. The three highest-ranked universities overall are Harvard University, Stanford University, and the Massachusetts Institute of Technology (MIT), all USA. This top three has remained the same for the last seven years. The highest-ranked institution outside of the U.S. and the UK is the University of Toronto, Canada, in fifth place. The top institution in a non-English-speaking country is Tsinghua University, China, at rank seven, up from 15th place last year. The highest-ranked European institution is the Swiss Federal Institute of Technology (ETH) Zurich at rank 25.

In the size-independent ranking (based on the proportion of publications that belong to the top 1 % most cited and a minimum output of 100 papers), Rockefeller University, USA, is ranked first, followed by MIT and Stanford University. The top institution outside of the United States is Shandong University of Science and Technology, China, in sixth place. The highest-ranked European institution in this category is the Swiss Federal Institute of Technology (EPFL) Lausanne at rank 17.

In the physical sciences, which include chemistry and related disciplines, the top rank in the size-dependent rating is held by Tsinghua University. In the size-independent ranking, Harvard University placed first in these fields, same as last year.

Size-Dependent Ranking (All Sciences)

(by the number of the university’s publications belonging to the top 1 % most frequently cited)

 

 

Size-Independent Ranking (All Sciences)

(by proportion of the university’s publications belonging to the top 1 % most frequently cited)

 

 

Size-Dependent Ranking (Physical Sciences and Engineering)

(by the number of the university’s publications belonging to the top 1 % most frequently cited)

 

 

Size-Independent Ranking (Physical Sciences and Engineering)

(by proportion of the university’s publications belonging to the top 1 % most frequently cited)

 

 

Methodology

The CWTS Leiden Ranking is based on bibliographic data covering the years 2016–2019 from the Web of Science database produced by Clarivate Analytics. Book publications, publications in conference proceedings, publications in journals not indexed in Web of Science, and publications in languages other than English are not included.

The ranking offers the following indicators of the scientific impact of a university:

• P
  The total number of publications of a university
• P(top 1 %) and PP(top 1 %)
  The number and the proportion of a university’s publications that, compared with other publications in the same field and in the same year, belong to the top 1 % most frequently cited
• P(top 5 %) and PP(top 5 %)
  The number and the proportion of a university’s publications that, compared with other publications in the same field and in the same year, belong to the top 5 % most frequently cited
• P(top 10 %) and PP(top 10 %)
  The number and the proportion of a university’s publications that, compared with other publications in the same field and in the same year, belong to the top 10 % most frequently cited
• P(top 50 %) and PP(top 50 %)
  The number and the proportion of a university’s publications that, compared with other publications in the same field and in the same year, belong to the top 50 % most frequently cited
• TCS and MCS
  The total and the average number of citations of the publications of a university
• TNCS and MNCS
  The total and the average number of citations of the publications of a university, normalized for field and publication year. An MNCS value of two, for instance, means that the publications of a university have been cited twice above the average of their field and publication year

The ranking also includes indicators for collaboration, open access publishing, and gender diversity. It provides statistics for the following five fields of science:

• Biomedical and health sciences
• Life and earth sciences
• Mathematics and computer science
• Physical sciences and engineering
• Social sciences and humanities

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• CWTS Leiden Ranking 2021,
  Centre for Science and Technology Studies, Leiden University, The Netherlands

 

Also of Interest

• CWTS Leiden Ranking 2020,
  ChemistryViews.org 2020.
  Scientific performance of over 1100 universities assessed based on bibliometric indicators