Wednesday, October 27, 2010

Class Size in Higher Education

The role of class-size in primary education has between discussed before on this blog. Earlier this year Kevin and Mark both posted interesting comments on the analysis of secondary data. In addition, I recently mentioned that data on primary-school class sizes in Ireland are available for the last four years by primary-school and class-room. Those looking for an introduction to how economists view the importance of class size in primary education could do worse than investigate this debate between Alan Krueger, Eric Hanushek and Jennifer King Rice.

"Alan Krueger maintains that smaller class sizes can improve students’ performance and future earnings prospects. He challenges Prof. Hanushek’s widely cited analysis of the class size literature, arguing that it gives disproportionate weight to single studies that include a large number of estimates... Jennifer King Rice brings a third-party perspective to the debate. She addresses each author’s arguments and focuses on the policy implications of the class size literature."

As educational achievement in higher education is often discussed on this blog, it seems salient to ask what we know about the importance of class size in higher education. To begin, it is helpful to point out that much of the work using education production functions has concentrated on the educational attainment of pupils in compulsory schooling, with less attention paid to higher education (Arulampalam, Naylor and Smith, 2009). The common inputs in education production functions are things like school resources, teacher quality, and family attributes, and the outcome is student achievement (Hanushek, 2007). However, there is a precedent for the theoretical consideration of higher education production functions (Freire and Silva, 1975; Johnson, 1978; Hopkins, 1990; Douglas and Sulock, 1995). There is also a much wider empirical literature on higher education production functions, in which researchers give attention to student inputs, in particular: lecture attendance and additional hours of study.

Looking at the evidence on class size in higher education, one result is that smaller classes do not translate into gains in achievement (Martins and Walker, 2006). Looking at economics students only, Kennedy and Siegfried (1997) find the same result i.e. that class size does not affect student achievement. Other work by Gleason shows that the same holds for mathematics students.

The opposite result (that class size matters) is found in a study examining peer effects and class size in higher education; Machado and Vera-Hernandez (2010) find that class size negatively influences medium ability college students. Dillon and Kokkelenberg (2002) show that class size "has a negative logarithmic relationship to grades and that the effect on class size on grades differs across different category of student."

In a recent Vox article, Bandiera, Larcinese and Rasul (2010) state that the effect of increasing class size in tertiary education is not yet well understood. Drawing on their article forthcoming in the Economic Journal, Bandiera, Larcinese and Rasul describe how they estimate the effects of class size on students’ exam performance by comparing the same student’s performance to her own performance in courses with small and large class sizes. "Going from the average class of 56 to a class size of 89 would decrease the mark by 9% of the observed variation in marks within a given student. The effect is almost four times larger for students in the top 10%."

It seems that the debate on class size in higher education is just as lively as the debate on class size in primary education.


Kevin Denny said...

One quick point: how do such studies deal with attendence? Class size is probably measured by enrollment. But often only a fraction turn up for class so its a very noisy signal.
Another question is: whats the mechanism? With primary schooling, you might think that in a smaller class, the teacher can give more attention to each student or maybe to the ones who need help.Maybe its easier to maintain disciplne also.
Funnily enough papers that look at class size usually say little or nothing about mechanism and invariably have no direct evidence about whether smaller classes actually are different in terms of behaviours or interactions. Something of a lacuna in the literature, I think.
In any event, its hard to see how such mechanisms would matter in a university course. So I am a bit sceptical!

Martin Ryan said...

Good comments Kevin. It is certainly the case that class size is measured by enrolment, from what I have read so far. Martins and Walker is the only study (that I am aware of) to explicitly consider the role of both lecture attendance and class size.

There is discussion on mechanisms in Bandiera, Larcinese and Rasul (2010), at least. Even if you look at just the Vox article, they suggest that:

"there appear to be at least two ways that larger classes reduce students' performance. First, changes in student behaviour such as their attentiveness or participation. Second, reduced resource availability, such as library books or faculty time during office hours. As the best students are the most affected, that could imply that large classes induce a reduction in tutoring activity rather than a substantial deterioration in classroom conditions. It is reasonable to expect that the best students are able to compensate classroom deterioration at least as well as other students. However, the best students are also those that benefit the most (in terms of both learning and motivation) from contact with teachers. They, therefore, suffer the most in terms of reduced performance when such contacts or tailored feedback is less frequent."

Martin Ryan said...

In the introduction to the Bandiera, Larcinese and Rasul (2010) paper, the following comment is also offered about mechanisms:

"There are several mechanisms through which class size can affect the behavior of students and
faculty. These behavioral changes can occur inside and outside the lecture theatre. For example,
students may be less attentive in larger classes, or may compensate for larger classes by exerting
more effort either in the library or with their peers. Faculty may be better able to identify the ability and interests of the median student in smaller classes, or be more able to answer students’ questions directly. Outside of the lecture theatre, faculty might devote more time preparing the delivery of
lectures and organization of materials for larger classes, or there may be congestion effects if faculty have less time to devote per student during office hours."

And the following is also stated:

"In university settings, there is evidence that students attitudes
towards learning tends to be negatively affected by larger classes [Bolander 1973, Feldman 1984, McConnell and Sosin
1984]. On teacher behavior, there is evidence from primary school settings that teachers know students better in
smaller classes [Johnston 1990, Boyd-Zaharias and Pate-Bain 2000, Blatchford et al 2005] but evidence on faculty
behavior across class sizes in university setting remains scarce."

Martin Ryan said...

Finally, I also thought the following was interesting Kevin, following on from your comment. It's from the introduction to the andiera, Larcinese and Rasul (2010) paper:

"We deliberately focus on identifying the causal effect of student enrolment, as opposed to attendance [Romer 1993, Durden
and Ellis 1996, Arulampalam et al 2007], because enrollment is a policy parameter that universities
can measure and manipulate relatively easily. In contrast, it is orders of magnitude more costly for universities to measure and regulate the physical attendance of each student in each of their classes."

It may be the case that universities can measure and manipulate enrolment relatively easily. But if only a fraction turn up for class, then it is a somewhat blunt tool for policy.

In relation to the cost of measuring and regulating attendance, one way to approach this is by experimentation with smart-card technology, such as TDS: