Alwyn Poole writes in:
Here are the three key things with class:
– marginal changes yield very little gain – ie. 29 to 27 make almost no difference. But 30 to 15 at Years 7 – 10 is mammoth and life altering.
– if teachers do not differentiate their teaching/learning but just think lower class sizes means less work – yep – very little effect. But if they use the extra time to get to know their kids, focus attention and change practices – once again – it is life altering.
– all of the effect sizes that Hattie has above c lass size are actually facilitated by a significant class size change and high quality dedicated teachers taking advantage of it.
All good points.