How Smaller Class Sizes Are Reshaping Upper-Division Coursework
Upper-division class sizes at many US universities have shrunk substantially over the past decade. The changes affect what students experience in their major courses.
Class sizes in the 300- and 400-level upper-division courses have decreased dramatically in the last decade at US universities, in significant ways impacting the coursework that students complete in their major. A 2025 report about to be published on 22 US universities found that the median number of students in upper-division courses has declined from 38 students in 2014 to 26 students in 2024. Because STEM courses often are organized into laboratory sessions and recitations, the decline in class size was less dramatic in these disciplines than in the humanities and social sciences.
The Pattern
A 2025 study surveyed 22 US universities that had provided data on class size for both 2014 and 2024. The data from those 22 universities showed that the number of students in upper-division classes decreased from a median of 38 in 2014 to a median of 26 in 2024. The greatest decline was in the humanities and social sciences majors where class sizes decreased by a median of 43 students from 2014 to 2024, a decline of about 53%. Although the number of students in upper-division STEM classes also declined (as measured by median) decreased—by 18 students or about 32%—the initially small class sizes in these majors meant that there was less of a decrease than in the other majors and therefore a relatively smaller percentage decrease. The decrease in number of students in upper-division classes therefore is one of the “quiet” changes affecting the way that undergraduate education is delivered.
The Causes
Several factors have contributed to the decrease in the average class size of upper-division courses. For one, the total number of undergraduate students in universities has grown very little in the last decade, while the number of majors that are offered has significantly increased. This means that instead of having fewer students distributed across fewer majors, there are now more students distributed across more majors. This has led to a decrease in the average number of students per major. The hiring of faculty in many disciplines has also contributed to the decrease in average class size for upper-division courses, as long as there is budget to support the hiring of these additional faculty.
The Outcome Differences
In terms of reported experiences by students in these very different formats of upper-division coursework, in the seminar format or discussion-based course with 8 or 10 students, students reported a number of positive elements to the teaching they were receiving. In particular, in these very small format courses, the students reported that faculty members knew their names, that class discussions included participation by most or all of the students in the course, that writing received more than minimal comments from the instructor, and that the faculty member was available for office hours. In short, while smaller format courses are more expensive on a per student basis than are the very large format courses, and so are not likely to be used for introductory or foundational courses (which are the courses that have seen greatest growth in recent years), they can provide a quality of educational experience that is not available in very large format courses.
The Engagement Question
While a number of differences between large and small classes are well documented, there are several key ways in which small classes provide better engagement with course material. For example, students in small classes are more likely to attend classes, participate in class discussions, and attend faculty office hours. As a result, students in small classes have better academic experiences in terms of the number of academic semesters they are enrolled in their major.
The Faculty Experience
Professors also report very different teaching environments in smaller classes as opposed to large lecture halls. For instance, writing assignments, individual research projects and seminar style classes with lots of discussion were either very difficult or impossible for faculty to teach in the large number of large section upper-division classes that have become common in the last decade.
The Cost Question
Smaller classes are also more expensive on a per-student basis. In many schools this cost is being absorbed in a number of different ways. For example, many large introductory courses are being taught by graduate teaching assistants. Also, online platforms are being used to deliver content to large numbers of students. In addition, some programs are simply being consolidated into smaller numbers of sections, in order to maintain the offering of smaller upper-level seminars.
The Equity Implications
Smaller upper-division class sizes are often developed for underrepresented students in order to enhance their academic experiences. These efforts, however, have the effect of further concentrating small class sizes in the existing programs of advantage. In turn, these programs attract the greatest number of recruits, while the smaller classes in underrepresented student’s programs are limited by their respective majors and by students’ respective schedules. These resulting outcomes are not equitable.
What Prospective Students Should Investigate
Average class size for upper-division students in intended major areas is reported in the university’s common data set. It is useful to note that universities report averages for all students (i.e. undergraduates), but it is the upper-division class size in intended major areas that gives the better sense of the student experience. For example, if a university reports an average of 22 students per class for all undergraduates but 42 students per class for upper-division students in intended major areas, then we can say that this university gives qualitatively different experiences to students in upper-division classes in intended major areas than another way, this university has small classes for some students but not for others.
The small notebook that I use to gather such thoughts has much of this article in it.
The Broader Implication
There are many little things going on with the way that undergraduate education is delivered to students these days and few of them draw very much attention, as a rule. So long as things seem to be getting done, there’s generally little notice of changes in the details of how things get done. Here we note that the tendency towards smaller upper-division class sizes in many majors at many universities is having some consequence for the education that students receive while they are undergrads at these places, and that consequence will typically go unobserved by all but the students in the particular major at the particular university, with the result that a program at one of the many programs at a university will have a different “flavor” than many of its peers around the country.
The Trade-Off Acknowledged
Smaller class sizes mean that more resources are invested in these classes (other than those with huge numbers of students). Large numbers of undergraduate programs are staffed with graduate students and teaching assistants. If a university is maintaining large numbers of seminars with 12-20 students then that requires a large investment of faculty. But we have not seen any quality problems in those maintained smaller classes. We have seen them absorb large numbers of sections of huge introductory classes (e.g. Intro to Biology for Life Science Majors) with huge numbers of sections of huge introductory online platform sections with small numbers of sections of huge introductory lectures with small numbers of discussions sections. And so on. And many universities use online platform sections to supplement the regular lectures. (The university that I work at uses a platform to supplement all of the regular lectures). In addition, some universities use a strategy of selective consolidation (i.e. they offer a large number of sections of a given large class and then choose a small number of those sections to be maintained as smaller seminars with 12-20 students). So while there are trade-offs here, at universities where this is invested, we have not seen any quality problems in the maintained smaller classes.
The Student Recruitment Effect
Some schools are now even using smaller upper-division class sizes as a recruitment talking point. For the families of prospective students who specifically ask about class sizes, universities that have invested in smaller upper-division class sizes can direct students and their families to data that highlights the university’s investment in smaller class sizes and distinguish it from its less invested peers.
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