Class sizes revisited (now with Bystander Effect!)

A year or so ago, I asked about the impact of class size on learning, particularly in the philosophy classroom. The conventional wisdom among educators is that smaller class sizes are more conducive to learning, though (based on my limited knowledge of this literature) this conventional wisdom has not been easy to corroborate. In particular, the question of the impact of class size on student learning is hard to study at the post-secondary level. Suppose that a faculty member teaches two courses, one a 50-person lecture and the other a 4-student directed reading. That yields a student-to-faculty ratio of 27-to-1. But that number obviously conceals the massive differences between the learning experiences in the lecture course versus the directed reading.

So along comes a study tailormade to yield valid findings about the impact of class size on learning — and it suggested to me an explanation for why smaller class sizes might have a positive impact on student learning, particular in inquiry-oriented disciplines like philosophy.

The study in a nutshell: Two researchers at the University of Richmond looked at 10 years worth of student evaluations of learning at a business school. The school's dean gave faculty the option of "supersizing" their sections (from 30 students to 45) so that faculty could teach two sections rather than three. A successor dean then mandated that faculty teach 30 students per section.

Because the university maintained detailed student evaluations of the courses before, during and after the experiment, Monks and Schmidt were able to examine the impact of class size and course load on students -- knowing that professors of roughly the same quality were teaching students of the same quality in sections that covered the exact same course material. In some cases, the choices of the professors also led to an increased number of students taught overall (based on number of sections and sizes), so the researchers were able to study the impact of class size and course load.

The results in analyzing student evaluations showed a clear (negative) impact of increasing class size. "[T]he larger the section size, the lower the self-reported amount learned, the instructor rating, the course rating," the paper by Monks and Schmidt says. The same is true, to a slightly lesser degree, for instructors who teach more students overall (across all of their sections).

Delving further into the evaluations of student experience, the authors find that increasing course size or number of students taught overall "has a negative and statistically significant impact on the amount of critical and analytical thinking required in the course, the clarity of presentations, the effectiveness of teaching methods, the daily preparedness of the instructor for class" and many other factors.

A pretty powerful study, since the impact of the independent variable (class size) on the output being tested (student learning) isn't likely to be muddied by other factors (change in who's doing the teaching, curriculum, etc.)

Naturally, we philosophers will note the negative impact of larger class sizes on the "amount of critical and analytical thinking" in the courses. But why might larger class sizes mean reduced critical and analytical thinking?

Here's an answer I find plausible: Philosophy is a strongly discursive and investigative discipline. Most students figure this out after a while, but as class sizes increase, so too does their unwillingness to intervene so as to create the discursive and investigative atmosphere needed for genuine learning to happen. The classroom setting itself needs 'help' from prepared students, but as predicted by the bystander effect, the larger the number of potential helpers, the less likely help will be forthcoming. (Some education researchers have considered this possibility before.) The introductory philosophy class, in my observation, represents for many students a collective educational emergency: Students accustomed to highly teacher-focused, low-autonomy, learning environments where they can simply absorb settled knowledge struggle to adapt to the very different learning expectations in philosophy. But thanks to the bystander effect, few students are willing to help create the very environment needed to address this collective emergency.

Obviously, there's a lot more going on to explain low levels of critical and analytical engagement in philosophy classes, but the bystander effect and student's sense of diffuse responsibility, might go a long way toward explaining the specific findings of this study. What do you all think?