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.
- Leiden Ranking 2011 on dedicated website
- Methodology
- Selection of criteria by the user
- Emerging countries
Leiden Ranking 2011 on dedicated website
These are some of the findings of the new Leiden Ranking 2011 – 2012 which has been published on the website: www.leidenranking.com. 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.
Methodology
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.
Selection of criteria by the user
The Leiden Ranking website 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.
Emerging 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.