No, they are the baccalaureate origins of phds received over some period divided by everybody who graduated from the entire university (or college) for some period prior, irrespective of their major or career interest (or ability).
Not many humanities majors or future lawyers attending Cal Tech or Harvey Mudd, I’m guessing…
I wonder if Oberlin’s conservatory students are backed out from its denominator. My guess is no. No college of my multi-college alma mater is backed out from its denominator, regardless of how unlikely it may be for some of those college’s graduates to ever earn science phDs.
Probably not many students in Northwestern’s colleges of Journalism, Education, Communications, or Music are high contenders for science Phds either. Yet all these irrelevant students are probably shoved into Northwestern’s denominator. To give you a feeling for how insightful those statistics can be.
Plus Northwestern gets a lot of on-campus recruiting.
What might be interesting to see is a denominator consisting of the students who were academically capable of getting a science PhD, actually wanted one, and prepared for same.
You don’t have that.