Reacción a "Reactions: Study says smaller classrooms do not improve grades for children from low-income families"

This is an interesting and well executed study, and the results are interesting on academic resilience. In relation to class size specifically, though, it is difficult to draw any clear conclusions from the results. The focus on resilience rather than attainment is novel in relation to class size. However, in this study there are no theoretical reasons given why one would assume there is an effect of class size on resilience, and without this context, the results are difficult to interpret. There is also, worryingly, no reference at all in the paper to other studies of class size effects, including critiques of large scale quantitative studies where class size is entered into statistical models, as here, along with many other variables. My worry is that the clear conclusions drawn about class size - that it is not worth investing in smaller classes - are not warranted by, and go far beyond, the study methods and results. The cross-sectional design of the study makes it difficult to determine the causal role of class size (as opposed to an association).

Of course, teacher quality is important, as said in the paper, but we have found that many teachers feel that class size affects their ability to teach well. Teacher quality and class size are not mutually exclusive. In my view, a better understanding of class size effects will not come from more large-scale surveys like this, but from in-depth studies which account for what goes on in classrooms, in terms of the classroom context, teaching and learning, when class size varies. This would then allow reliable conclusions about class size to be drawn for practice and policy.