@northwesty,
Take a closer look at those s/f ratios. Most private schools use a ratio based on total FTE faculty to undergrad students. Most publics use a ratio based on total FTE faculty to total students, graduate + undergraduate, excluding faculty and students in graduate-only programs like law and medicine. The way the publics do it is not only a truer reflection of how much time faculty have for individual undergrads, but it also comports with the instructions on the Common Data Set. In short, most of the private s/f ratios are pure fiction.
Example 1 (private): Penn’s 2014-15 Common Data Set, page 28, line I.2, reports a s/f ratio of 6 to 1, based on 9,540 students and 1,652 FTE faculty (all full-time faculty + 1/3 of part-time faculty). Sounds great, right? Yet on page 5, line B.1 of the same document, Penn reports 21,296 total students, of whom 11,550 are graduate students and 9,746 are undergraduates (full-time plus part-time). It’s.clear that Penn is counting NO graduate students as “students” for purposes of calculating its s/f ratio. It is also clear, if you look at line I.1 on page 28, that Penn is including ALL of its faculty for purposes of calculating its s/f ratio, despite clear instructions on that page to “exclude both faculty and students in stand-alone graduate or professional programs such as medicine, law, veterinary, dentistry, social work, business, or public health in which faculty teach virtually only graduate-level students.” Penn claims ZERO faculty in such “stand-alone programs,” (i.e., it counts ALL faculty in its s/f ratio) and it includes NO graduate students in its s/f ratio, even if they are graduate students in fields like psychology, political science, history, English, biology, chemistry, or what have you, where faculty typically teach both undergrads and graduate students.
Example 2 (public): Michigan’s 2014-15 Common Data Set, line I.2, reports a s/f ratio of 15 to 1, based on 37,063 students and 2,444 faculty. On line B.1 of the same document, Michigan reports a total of 28,395 undergraduates, of whom 995 are part time, which translates to 27,400 FTE undergraduate. So who are the roughly 10,000 additional students Michigan counts in calculating its s/f ratio? Well, obviously, they’re graduate students who are NOT in “stand-alone programs” like law, medicine, dentistry, etc.And notice also that in counting faculty for purposes of calculating its s/f ratio, Michigan is excluding 337 full-time and 235 part-time (=401 FTE) faculty who teach in “stand-alone graduate and professional programs.”
In short, Michigan is following the CDS instructions to a tee. Penn is not. And because Penn is not, you can’t compare Michigan’s 15:1 s/f ratio to Penn’s 6:1 ratio. They’re simply measuring different things. If Penn calculated its s/f ratio the way Michigan does (and the way the CDS instructs it to make those calculations), Penn’s s/f ratio would be at least 12:1, probably higher. Penn actually has more graduate students than undergrads (see line B.1).
I stress that these are not outliers. Check it out for yourself. Most privates calculate s/f ratios the way Penn does. Most publics calculate s/f ratios the way Michigan does. So you end up comparing apples to oranges, or perhaps more accurately, radius to circumference.