What sets "top" universities apart from "mediocre" universities in continental europe?

To be honest, I don't much like the idea that some people suggest there are "mediocre" universities. Good research can be done just about anywhere in many fields. Caveat: Some fields require funding beyond what is available at other than the biggest, richest, universities.

But there are several things that go into the rankings. I suspect that most of them are cumulative in some way. A lot of great research gets done at Oxbridge because of its size and history and attractiveness to scholars (and funders). Other schools don't have the same features. But the ranking is due as much to the quantity of good research as to the quality, as the quality can be good anywhere, but the resources available don't support as much of it.

A larger university has an advantage since it can more easily support working groups that can collectively produce great research. A smaller place leaves its faculty more isolated (less true today than historically - but history is part of this) with less opportunity for sharing and synergy.

Some of it is just luck over time. Good faculty attract good faculty. Researchers attract researchers. An older university, if well managed, has an advantage over a newer one. It takes time to build reputation. The magnetic attraction of a good place increases over time. Harvard University, like most others, had a modest beginning. Its founders would be unlikely to recognize what it has become. Certainly its mission is quite different than it was originally.

A good reputation attracts students. Often it attracts far too many students. This lets such a place choose really good students who wind up having really good careers, adding to that reputation. And for some of those graduates it means wealth and for some of those, contributions back to their university. Harvard graduates tend to be pretty smart. But they were already judged to be pretty smart before they went to Harvard. Ubiquitous? Maybe.

Resources matter a lot. Especially today, with a more mobile pool of researchers than was possible in the past. For example, Europe is largely without borders and the links between Europe and the Americas are strong. So people can go where there are other compatible people (and good funding). So reputation tends to build on reputation.

But not every brilliant researcher or teacher wants to put up with the constant pressure of a "top" university, so it is possible to find that brilliance spread out. Just because you happen to be at an R2 or a teaching college doesn't make you mediocre. It can make you sane, actually. Hence my objection to the "mediocre" characterization.

The ranking quite often depends in the university's attitude. All ranking are done by metrics and you can (and some universities often do) game the system. One example I remember is that one of those metrics, supposedly, had library working hours as a criteria and a university decided to keep a working hall open 24 hours just to register as if the library were open 24 hours.

If a university cares about its rating then they might try to increase their rating. But you must understand that everything has a cost and name of the game is cost analysis. Some required changes might cost a lot and even can be counter productive. Impacting both teaching and research. From what I see, European institutions care more about their national (or within EU) image rather than some arbitrary metric. I certainly have seen some universities in a country ranking higher than some of the elite universities of that country. Still it does not make a single difference. 99% of the candidates still regard the elite colleges higher and society deems graduates from these elite universities much higher.

What I suspect dictates the general phonemea is that American public (or at least candidate students) value these metrics. Furthermore it seems these metrics are often designed with focus to the American system. As of 2020, in THE rankings, India does not have a single university in top 300. This is a country of 1.3 billion. I would be suprised if they didn't have a single university that is worth a top 300.

The answer is possibly simple: university rankings are simply false, and some are allegedly fake.

University rankings produce false data (i.e., rankings) based on self-invented metrics that are dubious, and some are even speculated to fake their results.

Their falseness is two-fold:

• The parameters they measure are invented and subjective, and do not necessarily reflect inherent quality of any sort, or reflect personal preferences. E.g., "international outlook".

• Assuming the parameters are accurately measured (and this is doubtful), the falseness of the rankings is in the use of the term "ranking". This term presupposes a linear (total) order on universities' "quality". There is no justification to assume such a linear ranking exists.

Their alleged fake-ness is:

• University rankings are speculated (though I don't know if this is verified anywhere) to calibrate their data based on pre-conceived rankings. For instance, a ranking may calibrate its parameters ("play with them") in order to result in Oxford being number one. This is allegedly done for two reasons. The first being to convince the ones doing the ranking that their parameters are calibrated "correctly". Hence, resulting in a ranking that pre-supposes what they set out to find in the first place! Second, it is allegedly done in order to gain reliability and popularity in the public, by exploiting the pre-conception of e.g. Oxford as being number one.

Proof of falsehood: Take any two rankings. You will see that many university, say 30%, rank completely differently in them. One being say 100 in ranking A and 250 in ranking B.

Possible indication of fake-ness: Although universities that are less known may have extreme discrepancies between them exhibited in two different rankings, 90% of those universities that are perceived as top lack this discrepancies. Hence, Oxford would rank 1 in ranking A and say 3 in Ranking B. While lesser known university x would rank 100 in ranking A and 250 in ranking B.