Rankings first appeared in the USA as a help in choosing a university or college for students facing a huge and diverse market as is the case in America. Over time, national rankings initially became common in Anglo-Saxon countries, and at a later stage they acquired an international dimension.
What do rankings compare?
There are two main types of rankings: those that include whole universities and those involving specific programs, especially for those who are already oriented towards a specific subject area.
Who publishes rankings?
Ranking compilers belong to different categories: media, service providers, consultancies.
What data are used for rankings? Who provides them?
Rankings are not all alike. However, the starting data are often similar, because comparing very different universities forces compilers to use data available in the same form for all and therefore much interesting information cannot be considered. Some data are in the public domain, others are collected by specialized agencies, through questionnaires or by the universities themselves.
How do methodologies differ?
The raw data are often similar, but they are processed in different ways. Of very high importance are the weights assigned a priori to each variable: even small variations of these weights can change a ranking significantly. Some compilers collect information themselves, as is the case for example with QS World University Ranking which (uniquely among the best-known) asks businesses which universities provide the most interesting graduates. An exception is represented by U-Multirank, which leaves the user free to choose significant parameters.
What are the most reliable rankings?
No ranking is inherently better than the others, because the quality of a university depends on many factors and not all of them can be measured. Besides, each reader has his own priorities and needs. Broadly speaking, it can be said that QS and Times Higher Education publish the most widely known rankings of universities, while the Financial Times makes the most trusted rankings of individual programs. However, it must be considered that no methodology is exempt from problems of some kind.