Some schools are mostly tailored towards teaching the undergraduates while some are focused on research (mainly by virtue of their PhD programs). Of course, there are others who are good at both. In fact, most schools that do well in graduate programs tend to do well in undergraduate programs, and vice versa. When it comes to separating the graduate and undergraduate programs, schools typically separate them by majors as well. Hence, the rankings tend to get a bit more accurate. For instance, consider engineering majors. US News separate rankings into two categories: one for schools where PhD programs and offered (they are research schools) and one for schools where there are no PhD programs.
https://www.usnews.com/best-graduate-schools/top-engineering-schools/eng-rankings?int=997208
For schools that offer doctorate programs, MIT is ranked # 1 for engineering programs, followed by Stanford and University of California- Berkeley. The University of Michigan, which was not near the top 10 for overall quality rankings by Times and US News, is ranked #4 for graduate engineering. Harvard, which is near top by all previous rankings, is ranked #22 for graduate engineering program. The University of Utah, my alma mater, is ranked #45 in Business Programs while being ranked #110 nationally for overall quality by the US News. Students can further divide the engineering and business programs into their most basic majors (Electrical, Civil, Accounting, Finance, etc.). New York University, which is ranked #30 in the national overall ranking, is ranked #2 for Finance. In fact, NYU is ranked very well for almost all business majors due to its location in the financial center, New York. This should convince the students that they should never solely rely on just the overall rankings of the school but also consider respective majors.
For best business schools, Harvard claims the top spot, followed by the University of Chicago as #2. However, when separating the business programs into undergraduate and graduate business programs, rankings are different. The University of Pennsylvania, and not Harvard, is ranked #1 while MIT is ranked #2. Hence, a school that claims a top stop for an undergraduate program may not have the top ranking when studies are divided into undergraduate and graduate levels.
To make ranking business more complicated than it already is, a few studies provide so-called ‘global rankings.’