Denise Maruszczak is outraged by the suggestion that she is damaging her pupils. "We don't call it setting," the deputy head of Ebor Gardens primary in Leeds says. "We call it teaching at their own instructional level."
Pupils at Ebor Gardens are arranged in mixed-age ability groups from Year 1 for literacy and from Year 3 for maths. They are then assessed every eight weeks and repositioned accordingly.
Because the groups range across year groups, it is inevitable that pupils will move into higher sets as they progress through the school.
"As if you'd leave them in one group throughout school," Ms Maruszczak says. "It's an appalling idea, that you'd do that to them.
"Not everyone will go into the top group, but everyone will move on. They take ownership of their learning. That's what life's about: if you keep your head down and do your work, then you'll move on."
Ms Maruszczak insists that pupils benefit. For example, she says, it would be detrimental to the education of 11-year-old immigrant children to place them immediately in a literacy class with other Year 6 pupils. Instead, they are grouped with younger pupils and progress through the sets as their English improves.
"Children come to school with different experiences. So they're not all going to be at the same level," she says. "Surely it's more damaging to put a child in a group where they can't access the curriculum. And if you can't access the curriculum, you're more likely to misbehave."
But she is prepared to acknowledge that poorly implemented setting might be damaging.
"Children who have special needs at one point in their lives won't necessarily have special needs for the rest of their lives. It's about working together, co-operating with each other to learn. If groupings are correct, then it does work."