The 2003 publication of the ARWU (Academic Ranking of World Universities) was the first in a series of international rankings of higher education institutions, which attests to the emergence of genuine international competition in this domain. The approaches used for these rankings vary significantly in terms of selection procedures of the institutions to be assessed as well as measurement criteria and methods or result presentation. This diversity is fully reflected in the seven international rankings which are detailed and analysed in this article (ARWU, THE, CHE, Financial Times, CWTS, the webometrics ranking of World Universities and Ecoles des Mines). Some of them, like the ARWU and the THE are aimed for worldwide coverage, and others are oriented towards an European specificity like the CHE.

Very diverse entities with varied missions are defined by the expression "higher education institution". Any attempt to classify this heterogeneous group is arbitrary by nature: it depends on the aspects taken into consideration to characterise the institutions (teaching, training, innovation, development, social responsibility etc.), on the indicators used to position the institutions in relation to these aspects and finally on the methods used to assess the importance of each of these aspects. Rankings are therefore the result of multiple choices, justified vis-à-vis pre-established quality representations and implicit or explicit objectives. In light of the many applications which can result from the rankings, and therefore the multiple possible objectives, no single generic ranking, regardless of its quality and relevance, will ever be able to respond to all the requirements and questions.

These classifications constitute however a good method to tackle such complex systems and raise basic questions on the possible improvement in public policies and institutional strategies. Nevertheless, they do not correspond with a genuine evaluation approach. The classification principle on a single scale makes it possible to compare very different entities. A comparative evaluation between higher education institutions can only be made based on a typology-oriented approach in order to identify, amongst the institutions or even within these institutions or inter-institutional organizations, the elements whose proximity makes the comparison pertinent. Furthermore, typology makes it possible to understand the importance of the necessary diversity of the system in relation to all the requirements of society, unlike the hierarchical classification, which favours a uniform model. Finally, it provides the possibility of reorganising the criteria according to targeted objectives, therefore meeting a broader spectrum of requirements.