This article suggests the use of statistical analysis, based on revenue data, to measure institutional diversity. The financial statements of universities in Italy and in England are thoroughly examined in order to emphasize the levels of diversity within these two different university systems; to understand the causes of the variations; and to verify, from a longitudinal perspective, the behaviour of the universities in terms of differentiation. The aim of this paper is mainly methodological; that is, to demonstrate the potential of revenue data analysis for investigating institutional diversity. For exploratory purposes, this paper will also introduce additional considerations to the ongoing debate on institutional diversity.