@Mastadon I agree it isn’t perfect, but I do think it is the best vehicle we have. And maybe not even for the reason it is intended.
Like it or not, a large subset of students/parents/other stakeholders do use it as a data point in their decision making process. Students and parents for obvious reasons, but other stakeholders who make decisions on research and donations. Prospective faculty will use this information to help justify leaving one university for another. Granted that each subset uses that data to make decisions to support or, more often, not support a university.
The Universities (with the lone exception of the instances mentioned in this thread) themselves have validated the ranking system by modifying their processes to move up and down in those rankings. Every Director/VP/Dean of Admissions understands the flaws you mentioned in the calibration method, and have decided they collectively have little problem with it. As long as the three schools continue to calibrate each other (which you’d have to admit is better than only one standard) then your model is directionally correct. Now, we may begin to see other schools creep in there as well, maybe this year if things continue on the trajectory they have been for a few years.
I think we as consumers need to realize there is literally no difference in the level of education you can get at any institution between 1-15 or 1-20 in the USNWR ranking. Similarly, not much between 21-100 probably. Before I get all sort of hate from lovers of that second group, I am giving a broad statement, not a precise one and as you can tell from my handle, I’m a firm supporter of a member of that group. The point is that these are all great schools and a difference of 1 or 10 places isn’t that different in the eyes of the student.
Without it, things like student:faculty ratio and graduation rates and earning at graduation and whatever other factor weighs in will have little or no check. Schools in the state of Illinois system will begin to decrease faculty and add to admissions to pay the bills.
Few will argue effectively that the US Higher Education system dominates the world market. I suggest that this ranking helps that happen.
Now to your question as to why do Research Universities and LAC score differently? Can you really expect to compare Williams with the University of Michigan? Bowdoin with UChicago? (although I often wonder why the college at UChicago isn’t stacked up against the rest of the LACs).