Class Size Matters, Stupid!

In Uncategorized by Alex Quigley9 Comments

‘The year 9 class of the future?’

A discussion around class size is never far away from educational debate. Every so often a new report is emblazoned with headlines in the press: ‘class size matters’…’class size doesn’t matter‘. What are we to believe? Well, of course class size matters, stupid. And yet, as with most things in education, it is more complicated than that.

The debate has broken out once more on social media, based on a review of class size research undertaken by Diane Whitmore Schanzenbach, called ‘Does Class Size Matter‘, resulting in headlines in established media outlets like the Washington Post: ‘Class Size Matters a Lot, Research Shows‘. Interestingly, this research summary is over a year old, but the debate that were initiated back in February 2014 are being repeated once more. In fact, the evidence stated by Schanzenbach is broadly the same as what has been offered by the EEF Toolkit, but Schanzenbach doesn’t really discuss potential alternatives approaches, nor the issues that attend class size reduction.

Now, you would be hard pressed to find a parent, teacher or student, who would demand larger class sizes. I am a parent and I am a teacher. Do I prefer groups of 20 over groups of 25, for example? Of course – it would be my preference almost every time to have 20 students. Only, the issue with reducing class size like this is that it doesn’t transform student outcomes – it is no silver bullet. I wouldn’t change my practice with the class size reduction I describe.

Does class size matter? Of course – but not as much as we think and we seldom give a thought to other factors that attend class size reductions.We need to ask better questions.

First, how big a class size reduction are we taking about? The impact on student outcomes will likely correlate with how big a reduction. If we have a class of 30 reduced to 25, then the impact will be relatively small, if there is any at all. We like to think that teacher interactions are transformed and time on task and the quality of feedback all improves with a smaller class, but the reality is that teacher quality is rather stable – therefore a not-so-great teacher with 30 students will not be transformed by having five fewer.

If we are saying the class size reduction is from 30 students to 15 students then we are definitely getting somewhere. The evidence suggests that it could have a very positive impact, especially for younger children and minorities.

Again, though, we miss the crucial support factors. Is the teacher changing their practice appropriately with the smaller group? Are they giving better personalised feedback, eliciting greater trust and generated more focused time on task? Or do we have a little less stress (no doubt important too)? If teacher training isn’t prioritised then there may be no change regardless of class size.

We then bump into more complex problems. As Dylan Wiliam states, the policy reduce class size doesn’t come cheap:

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Not only are the costs significant (no doubt prohibitive in our generation of declining budgets to pay for banker-induced debts) but that isn’t the only problem. Large scale class size approaches in Tennessee and California exposed a hidden issue: if you reduce class sizes then you need many more teachers.

Teachers don’t grow on trees, so needing more teachers could mean a lowering of standards, if we can get the requisite teachers at all. If we cannot get more teachers (our current recruitment and retention crisis is chastening) then we would likely begin to have fewer high quality teachers in front of our students. The gains offered by the class size reduction could be washed away in this scenario.

I want my children to have a great teacher in front of them first and foremost. I would rather a better teacher in a larger class. In the best of all possible worlds, we would have both, but that is not our current predicament.

Don’t misunderstand me, I don’t want my children having a Science lesson Skyped to them by a teacher from Northampton in a hall stuffed full with 60 students. I reject the absurd notion that class size doesn’t matter at all, but we need to recognise that reducing class size is not a silver bullet.




  1. Of course class size matters. My nephew is the same age as my son (5) and is bright just like my son is. The only difference is that my nephew goes to private school where he is taught in a class size of 12!!! My son is in a class of 32. Even though we do work with my son at home, he is definitely not developing at the same rate as my nephew. I find this really sad. How can one teacher and one TA ensure that all the needs are met if 32 children!
    We can’t afford to send our son to be privately educated as we are both teachers. However, the government is being ridiculously naive if it thinks that a variety of teaching strategies will stop the gap growing between the rich and the not so rich.
    I think a class size of 15 at primary is ample. I teach secondary and struggle to meet the needs of my 31 middle set year 8 pupils no matter how hard I try.
    The government needs a huge wake up call! Why do they think literacy levels are dropping. Each individual child does not get the support it needs. The divide is just going to grow and grow.

    1. Author

      Yes – private schools have the selling point of smaller classes, which reflects its value for parents. The class size difference between 12 and 32 is no doubt vast and, given the teachers are somewhat similar in terms of quality you would expect better student outcomes. That is not to say many teachers, including yourself may well be teaching students in a class of 31 better than a colleague with 23. It will feel different, but you may be getting better outcomes.

      There is no quick fix. Class sizes of 15 may well be ample, but that is dream territory isn’t it? I think we should fight the battle to stop ever-increasing class sizes and focus on interventions that have a greater impact that class size reductions, but that prove much cheaper.

      I don’t think we should roll over and accept class sizes of 31 here, there and everywhere, but I think we should not forget that we can teach a class that size better than some teachers in other schools with fewer students. Let’s do that as best we can.

      Thanks for responding and I wish your son the very best. I would not underestimate the impact you will have at home and how developmental gaps ebb and flow. May he do brilliantly and let’s make sure that state schools close that divide.

  2. I think the big issue is going too far the other way. I imagine it isn’t as morally acceptable to study the effect of increasing class size, however having taught in 2 schools with major staffing issues this is what happened. Interestingly it didn’t seem to have a huge bearing on outcomes (at least for Y11), but teaching 8 classes of 34+ a week in a science lab designed for 28 was bloomin exhausting, especially when there were no allowances in terms of reduced marking expectations etc. Perhaps this fuelled the schools’ staffing issues in the first place!

    1. Author

      I have no doubt that issues related to teacher well being and room capacity etc. all attend class size. I don’t advocate lager classes – I just think we should ask better questions.

    1. Absolutely. In terms of teacher workload and time, the difference between 30 and 25 is very significant. It’s at at least equivalent to not having to mark between 20-30 books a week.

  3. There are issues with the report as it does not undertake a structured systematic review of the evidencr

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