Last Wednesday, we published the new edition of the Leiden Ranking. The results are quite interesting. The range of countries with universities who score high on their number of highly cited publications is increasing. Thirteen countries are now listed in the top hundred of the world: the US (57 universities), UK (16), Switzerland and the Netherlands (each 6), China (4), Singapore, Canada and Germany (each 2), and Israel, Denmark, Ireland, South Korea and Australia (each with 1 university).
Clearly, the US is still dominating. The first 12 universities are all based in the US. Like last year, MIT is leading the ranking with no less than one quarter of its publications in the 10% most cited percentiles of their field (in this calculation, we also take into account the publication year). The largest research university in the world, Harvard, is number five with an impressive one-fifth of its papers published between 2008 and 2011 scoring in the 10% most cited papers of their field. Note that when the option “fractional counting” is vinked, a paper is attributed as an equal fraction of a paper to all universities mentioned as author address. This prevents double counting, but does not reflect the total number of papers originating from a university. For example, Harvard has produced almost 57,000 papers, but many of them with other universities, which results in a “fractionalized” number of almost 30,000 papers, of which one-fifth scores in the 10% most cited segment.
China is steadily increasing the impact of its research. Whereas in the recent past, China rose quickly in terms of the production of scientific papers but not so much in terms of scientific influence, we now see that research from Chinese universities is gaining citations. Two Chinese universities, Nankai and Hunan, are even scoring higher on the highly cited indicator than the highest ranking Dutch universities (Leiden University and Utrecht University). Almost 14.5% of their publications belong to the top 10% most cited in their field. The diversification also shows outside of the top 100 universities. For example, China has 37 universities in the Leiden Ranking 2013 (of which 6 are newcomers), Iran (all five are new), Brazil (10, 2 newcomers). This trend is the result of three effects. First, many universities are increasing their share of the scientific production. Second, at the same time, the number of scientific papers is rising as such, which results in a steady increase of the size of the Web of Science database, on which the Leiden Ranking is based. Third, we have become better in correctly identifying universities in the address field of the scientific publications. We suspect, for example, that this contributes to the rise of Iran in the Leiden Ranking.
Of course, the ranking also shows areas in which the citation impact is lower than expected. What struck me is that the Japanese universities (including the prestigious Tokyo University) all score lower than the world average. This is also true for all universities from some of the newcomers such as Iran. But also, somewhat more surprisingly, for Norway, Brazil, Poland, Italy, Greece, Portugal, Russia, Turkey, and Taiwan.