How to tag campus buildings that also in practical use?

• For the building type: use the type which is the most characteristic one for this building. Tag it as university building if it looks like all other university buildings around. I guess the building type will matter for much less data users than the amenity tags.
• amenity (schematic example image):
  • The university amenity tag should exist only one time for the whole university. So, likely this will be on an area (closed way) or even a multipolygon.
  • And, yes, the hospital amenity tag is additional to the university then (there is an university and an hospital and you can easily map it what way). Map the hospital amenity area inside the university amenity area (sorry, I cannot find a good example). You do not need to cut out the hospital areas from the university area, since the hospitals belong to the university too. Depending on how big the hospital area is, use it on an area (maybe simply the hospital building or as a new way if there are multiple buildings and places forming the hospital) or is it just a small part of the building which is an hospital, then maybe a node would be the best way.

Also see our docu wiki for those tags: hospital and university, of course.