Given what I know, why am I still grouping by ‘ability’ in primary maths?

Three years ago, in the spring term of my PGCE training, I was asked to complete a research study into an aspect of inclusion. I wanted to investigate an important issue in primary education, so it would have a wider relevance and application than my own practice.  I recalled something that my mother had said when she was working as a Teaching Assistant: The teachers never say it, but even the Circle table have worked out that the more sides you have, the better you are.  They know Hexagons are the best. Reflecting on this now, through the prism of fixed/growth mindset training á la Carol Dweck, I can see the irony. My mother was despairing of the practice of setting children by ‘ability’, even into table groups, as she believed that it limited and demoralised the as-yet lower-achieving groups. Yet she implicitly agreed with the Circles’ assessment of themselves as the ‘worst’ at maths, and the Hexagons as the ‘best’. As such, I decided that my research project would