New Leiden Ranking

Paul Wouters p.f.wouters at CWTS.LEIDENUNIV.NL
Fri Dec 9 05:57:33 EST 2011

Dear colleagues

 US still dominates high impact publications in science

The US are still the dominant scientific world power, but new centres of
science are emerging. MIT is the university which has the highest citation
impact of its publications in the world. Princeton and Harvard take
positions two and three. These are some of the findings of the new Leiden
Ranking 2011 – 2012 which has been published on the website: The top fifty list consists of 42 US based
universities, 2 Swiss (Lausanne at 12 and ETH Zurich at 18), 1 Israeli
(Weizmann Institute of Science), 4 British (Cambridge at 31, London School
of Hygiene & Tropical Medicine at 33, Oxford at 36 and Durham at 42), and
one Danish university (Technical University of Denmark). Aggregated to
country level, the US has 64 universities in the top 100 list, the UK 12,
and the Netherlands 7. The latter is remarkable given its small size.

The Leiden Ranking 2011-2012 is based on an advanced methodology which
compensates for distorting effects due to the size of the university, the
differences in citation characteristics between scientific fields,
differences between English and non-English publications, and distorting
effects of extremely high cited publications. Publications authored by
researchers at different universities are attributed to the universities as
fractions. This prevents distortion of the ranking by counting these
publications multiple times (for each co-authoring university). This
distorting effect is often overseen in other global university rankings,
which leads to a relative advantage of clinical research and some physics
fields in these rankings. This makes clear how sensitive global rankings
are to the nitty-gritty of the calculations.

The Leiden Ranking enables users to choose the criteria on which they wish
to compare university performance. The menu offers 3 indicators of impact
and 4 indicators of scientific collaboration. When scored on the percentage
of their papers produced in collaboration with institutes in different
countries, the London School of Hygiene & Tropical Medicine tops the list
with more than 50 % of its publications co-authored with other countries.

Although in terms of impact, US universities are still strongest, it is
clear that other countries are emerging as centres of science by looking at
the total production (number of publications in the Web of Science). In
this ranking, Harvard University is number one. But in the top 25 we also
see universities from Canada (Toronto at 2, British Columbia at 22), Japan
(Tokyo at 4, Kyoto at 11, Osaka at 25), Brazil (Sao Paulo at 8), United
Kingdom (Cambridge at 13, Oxford at 14, University College at 17), South
Korea (Seoul at 19), and China (Zhejiang at 20).

The Leiden Ranking is the first global university ranking which has
published the details of its methodology and indicators. The indicators are
presented in combination with stability intervals, an advanced statistical
method to measure to what extent the differences in rankings between
universities are significant.

If one wishes to compare the university citation impact in a global
context, it is best to take the percentage of papers in the top 10 % highly
cited papers together with the calculation method “fractional counting”.
This is the method which compares across institutions and fields in the
fairest way.

The Leiden Ranking is based on data of the Web of Science. Data on the arts
and humanities are not included since these fields are not well represented
in the Web of Science. The Leiden Ranking exclusively measures the citation
impact of research of the 500 largest universities in the world. This
prevents an arbritrary combination of performance in education,
valorization and research, a disadvantage of many global university

More information about the ranking results and its methodology:

With regards

Paul Wouters
Professor of Scientometrics
Director Centre for Science and Technology Studies
Leiden University

Visiting address:
Willem Einthoven Building
Wassenaarseweg 62A
2333 AL Leiden
Mail address: P.O. Box 905
2300 AX Leiden
T: +31 71 5273909 (secr.)
F: +31 71 5273911
E: p.f.wouters at

CWTS home page:
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