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Student to Faculty Ratio: A Number Both Helpful and Misleading

Student to Faculty Ratio: A Number Both Helpful and Misleading

Many students and parents focus on the student to faculty ratio as an important metric while researching colleges. There is an impression that the student to faculty ratio is somehow an indication of the class size.

In reality, the student to faculty ratio is not an indication of an average class size. It especially may not give a sense of the size of popular introductory courses. Think physics 101, math 101, psychology 101 courses, where the class size could sometimes be over 200 students at some colleges. And yet the student to faculty ratio can be a helpful metric when comparing colleges with the same "group".

Let us look at the student to faculty ratio for some of the most popular colleges. There is quite a spread in the reported student to faculty ratio, isn't there?

Name of CollegeIEPDS Student to Faculty RatioUndergraduate PopulationFull Time Instructional FacultyPart Time Instructional Faculty
Princeton University5:15,400924188
Rice University6:13,893371180
Williams College6:12,15029974
Duke University7:16,6093,731197
Pomona College7:11,56321745
Vanderbilt University8:16,8711,226220
Washington University in St Louis8:17,5551,583569
Emory University9:16,8612,237535
University of Southern California9:118,7942,3691,408
Stanford University10:17,0343,296488
Willamete University10:11,99721785
U of Michigan Ann Arbor 12:128,9836,3441,524
Gonzaga University12:15,183443344
Marquette University14:18,238648510
University of Virginia15:116,3312,217140
University of Oregon17:120,0491,140373
University of California Berkeley18:129,3101,646848
University of Texas- Austin18:140,1682,748323
Georgia Institute of Technology20:115,489841140
Arizona State University-Tempe23:142,4771,941139
Table 1: Student to Faculty Ratios at select 4-year public and private colleges in the US. Analysis of IPEDS data by O's List.

Definition

To understand the student to faculty ratio, let’s begin with the definition of the student to faculty ratio (yep…there is a formula!)

Student Faculty Ratio Formula

Full time/Part time students are full time/part time enrolled undergraduate and graduate students. Colleges have a fair bit of leeway in who they consider full time and part faculty and the numbers may be slightly different as reported on the Common Data Set and IPEDS (part of Ed.gov). For a deeper dive, read this paper by IPEDS.

When is it Misleading

Often students and parents can get confused that the student to faculty ratio somehow correlates to the class size. When the ratio is reported as 20:1, you may feel that the class comprises of 20 students. As can be seen from the definition of the student to faculty ratio, that may not be the case as graduate students and faculty who teach both undergraduate and graduate courses are included in determining the student to faculty ratio. Thus it is not a ratio exclusive to undergraduate students. There are many graduate classes where there are only 10 students in a class. Contrast that to an undergraduate class with over 100 students in the class!

Here are a few examples of colleges making a very clear distinction between the class size and student to faculty ratio.

Screenshot of University of Michigan's FAQ page on class size
Figure 1: Screenshot of University of Michigan's FAQ page on class size page.
Screenshot of UC-Berkeley's College of Letters & Science Facts at a Glance
Figure 2: Screenshot of UC-Berkeley's College of Letters & Science Facts at a Glance page.
Screenshot of UC Oregon's
Figure 3: Screenshot of University of Oregon's admissions facts page.

It is possible that a freshman may end up in a class with 40, 50 or even 100 students in the first year. It usually gets better from there on as the students start to take classes in their intended field of study and the freshman 101 courses are done.

When is it Helpful

The student to faculty ratio is helpful when it is used to compare colleges in the same peer group. The private and public colleges have different average student to faculty ratio. Even within each peer group, there are distinctions. E.g. the Ivies have a lower average student to faculty which is not totally unexpected.

Distribution of Student to Faculty Ratio across all 4-year public and private colleges in the US. Analysis of IPEDS data by O's List.
Figure 4: Distribution of Student to Faculty Ratio across all 4-year public and private colleges in the US. Analysis of IPEDS data by O's List.

The student to faculty ratio is not a standalone metric. While many factors contribute to it, the student to faculty ratio is determined by size of the graduate students and undergraduate students, whether all the faculty teach undergraduate classes, the ratio of full time to part time faculty, the cost of college and to some extent the academic profile and philosophy of the college.

However, it can be a powerful number to help spot any outliers to the general trend. Its not that colleges with higher than average student to faculty ratio are poor options … it is just a flag to look deeper and understand and correlate to other factors.

In conclusion, while it is tempting to think of the student to faculty ratio to be representative of the average number of students in a class taught by a faculty member, please do not assume that to be the case in all majors, all classes at any college.