Is concentration of university research associated with better research performance?

This paper analyses relationships between university research performance and concentration of university research. Using the number of publications and their citation impact extracted from Scopus as proxies of research activity and research performance, respectively, it examines at a national level for 40 major countries the distribution of published research articles among its universities, and at an institutional level for a global set of 1500 universities the distribution of papers among 16 main subject fields.