Leiden ranking

The Centre for Science and Technology Studies (CWTS) of Leiden University has developed a ranking system based on bibliometric indicators. This Leiden ranking focuses on all universities worldwide with more than 400 Web of Science indexed publications per year. Consequently the 500 largest universities (in terms of publication numbers) in the world are covered. Several ranking lists are published by the Leiden ranking. Each list is based on the same data but calculated using different impact indicators. For instance one list focuses entirely on impact, while others also take into account scale (size of the institution).

The PP10% indicator reflects the proportion of the publications of a university that, compared with other similar publications, belong to the top 10% most frequently cited. CWTS regards the PP-top 10% indicator as the most important impact indicator of the Leiden Ranking because it is the most stable impact indicator and cannot be strongly influenced by a single highly cited article.

Since 2011 CWTS also publishes rankings based on collaboration indicators. More information on the Leiden rankings can be found at www.leidenranking.com.