Class size: what’s best?


The latest SEDA blog discusses ‘Class Size matters’, one of Graham Gibbs’ 53 Powerful Ideas All Teachers Should Know About ( Graham focuses predominantly on HE, and contends that large class sizes are detrimental, leading to reduced student-teacher interactions, diminished levels of feedback, reduced access to resources, reduced depth of student thinking, and reduced achievement (Gibbs’ own study published in 1996 shows a small but significant drop in grades obtained in class sizes >30) . He attributes many of these problems to the ‘scaling up’ that may often be the response to reduced funding, but also notes that these detriments are not inevitable,  mentioning the success of the OU despite their massive cohorts (but small tutor groups and their own high-quality resources). Many of Gibbs’ points are echoed by Cuseo (2007), who also suggests that large class size reduces student satisfaction and retention.


By contrast, Hattie’s 2005 meta-analysis of the effect of class size in schools seems to indicate that there is very little effect of class size on learning outcomes, most of which are related to achievement. Hattie’s explanation for this revolves around teaching methodologies, and he commented:

“The argument is that moving from one ‘‘level’’ of class size to another requires a shift in the concept of excellence of teaching—a move from direct (most often transmission) teaching of students (at 80+) through attending to teaching and learning (at 20–80), to co-working with a cohort of individual students teaching and learning together. The shift required by teachers is not merely to adapt their methods as they move across the levels, but a major re-conceptualization of what it means to be excellent as a teacher at the various levels of class size.”


This may well be a valid point a point, but I am rather concerned about exactly which ‘learning outcomes’ should be used to gauge the effect of class size: is ‘achievement’ always appropriate, and which forms of achievement should we consider? I would also suggest that teaching approaches, whilst important, are not the only variables involved: student age and motivation are also important factors, along with the way that learning is organized, Hence, medical students, for example, may be highly motivated to learn even when a lecture theatre is packed, and even with a ‘poor’ lecturer, though they would undoubtedly learn more from a ‘good’ lecturer. However, they would also need sessions in small groups to discuss key concepts, or learn specific skills. At the other end of the spectrum, a parent or nursery nurse would have difficulty managing effective learning interactions with more than two or three infants. In between, I believe that a lot depends on the needs of individuals and groups, and research carried out by Peter Blatchford et al the Institute of Education around ten years ago gives an important perspective:

Results showed that as class sizes became smaller there were more times when pupils were the focus of a teacher’s attention, and more times when they were engaged in active interaction with teachers. This effect was found for all groups at both primary and secondary levels. It was also found that pupils’ classroom engagement decreased in larger classes and this problem was particularly marked for the pupils who are already attaining at lower levels” (


 In short, if we want learners to enjoy, and benefit from, their lessons we need to understand their needs, be clear about what the ‘learning outcomes’ should be, and ensure that there is sufficient resource available to provide the most appropriate learning methodologies. This might involve a reduction in class size for at least some of the time.



·         Blatchford, P; Bassett, P; Brown, P. (2008) Do low attaining and younger students benefit most from small classes? Results from a systematic observation study of class size effects on pupil classroom engagement and teacher pupil interaction. Proc. American Educational Research Association Annual Meeting 2008, New York [online]. Available at: [Accessed 25.9.14]

·         Cuseo, J. (2007) The empirical case against large class size: adverse effects on the teaching, learning and retention of first year students. Journal of Faculty Development, 21, 1, p5-21.

·         Gibbs, G (2014) 53 Powerful Ideas All Teachers Should Know About: Class Size Matters. SEDA blog [online]. Available at: [Accessed 25.9.14]

·         Hattie, J. (2005) The paradox of reducing class size and improving learning outcomes. International Journal of Educational Research 43, 387–425



Skip to toolbar