One of the frequent criticisms against rankings is that they compare institutions that are intrinsically different. How can you compare, for example, a Chinese executive education centre run by practitioners with an American university-based business school composed of academics that produce scientific research? These two hypothetical institutions may both offer MBA programmes, but their location, mission, faculty profile and research output vary essentially and are thus not comparable. The basis of this criticism is the incommensurability argument: different values or things of a different genre cannot be weighted according to the same scale; you cannot compare apples to pears.
The incommensurability argument is appealing from a theoretical perspective and has generated long debates in different disciplines such as jurisprudence or aesthetic. However, it is irrelevant in practice. Every day we have to evaluate different things and take decisions. Should I go to the theatre tonight or dine with my friends at home? If I invite my friends for dinner, should I prepare sushi or paella? The irrelevance of the incommensurability argument for the practice has been evidenced by some authors of aesthetics theory like Oscar Tusquets, who stated that "everything is comparable". The epitome of this comparability thesis is probably the maxim stated by Marinetti in his Futurist Manifesto of 1908: "A screaming automobile that seems to run on grapeshot is more beautiful than the Winged Victory of Samothrace".
Indeed, different offerings and diverse institutions are comparable from the perspective of the applicant who wants to decide where to study an MBA. One of the virtues of rankings is that they provide information to reduce the scope of the analysis for applicants. For example, they may help identify which are the institutions best regarded in Europe, America or Asia, or which business schools excel in a certain management discipline or which MBA programmes are better considered by some selected recruiters.
However, the crux of comparability is the data considered as the basis for comparison, the question raised by Della Bradshaw in her latest post about different sets of standards’ data usable for rankings. Certainly, concepts like "full professor", "foreign students", "starting salary" or "aims achieved at the end of the programme", just to name a few, may have different meanings and measured differently across the board. Who can legitimately give a standard meaning to those and other open concepts? My suggestion is that accreditation agencies such as EQUIS, AMBA and AACSB International may play a major role here. EQUIS, for example has a tradition of coping with diversity and is currently developing a glossary aimed at defining the basic concepts used in the accreditation of business schools. Can we expect to have a universal set of standards soon?