Everyone can master mathematics – so why can’t everyone be assessed as having mastered it?

By Malcolm Watson (Primary Teaching for Mastery Specialist, Cambridge Maths Hub), April 2026

One of the underpinning principles of Teaching for Mastery is simple and powerful: everyone can learn and enjoy mathematics. This is Essence Statement 1 (The Essence of Mathematics Teaching for Mastery | NCETM, and it is something I wholeheartedly believe. I’ve worked with the Cambridge Maths Hub for the last 10 years, and I’ve seen what happens when schools commit to high-quality teaching, coherent curricula, and the belief that every pupil can succeed.

So why, if we believe that every child can master mathematics, does it often feel as though our system is set up to ensure that not every child can be assessed as having mastered it?

When collaboration starts to feel like competition

At this time of year, I visit and support many schools and trusts. I’m proud of that work—but I also notice a tension that I don’t think I should be feeling at all. Because of the way outcomes are reported and compared, it can feel as though the schools I’m working alongside are, in effect, competing against one another (and even against my own trust) to get pupils to “age-related”.

That jars with what the Maths Hubs are about. The whole point is collaboration: working together to raise standards for all children, so that more pupils can master mathematics and be recognised as having met age-related expectations. If the system makes professionals feel they are in a competition, then it’s the system—not the people—that needs to change.

The problem: mastery teaching meets a bell-curve assessment model

Our current assessment system does not make it possible for all children to be assessed as working at age-related expectations, largely because of how outcomes are calculated and how grade boundaries are set. In practice, the system operates in a way that can resemble a bell curve: some pupils must fall below the line, regardless of whether overall attainment is rising.

This is why Michael Gove’s line, “We want all children to be above average,” was so often repeated—and so often misunderstood. It isn’t a criticism of ambition, but it is mathematically inaccurate. Not everyone can be above average; that is the whole point of an average.

Yet, when the system assumes a distribution, it becomes difficult to reflect genuine national improvement. I have no doubt at all that attainment is improving for many children in mathematics. But our current model doesn’t always allow that improvement to be shown—unless those in charge of setting the grade boundaries decide to make it visible.

Why this matters: “mastery” becomes more about scoring than understanding

Consider what it can take to be judged “age-related” at the end of Year 6. Children may only need to answer around 60 questions out of 110 correctly to reach the “golden boundary”. If “mastery” is demonstrated by just over half marks on a test, we have to ask an uncomfortable question:

Is that really reflecting mastery?

I’m not arguing that children should be required to score 100%. But I am arguing that the way we currently define and report “expected standard” does not align with what we say we value in teaching for mastery: secure understanding, fluency, reasoning, and the ability to apply mathematics.

A more transparent alternative: clear targets that everyone can aim for

What if we adopted an assessment approach that was more transparent and more aligned with mastery principles?

We already have examples of this in the system. For the Multiplication Tables Check (MTC) and the phonics screening check, everyone knows from the start what the end goal is. There is a clear target. Pupils either reach it or they don’t—and crucially, it is possible for everyone to reach it.

I would like to see something similar for end of key stage mathematics: standardised tests where the target for “age-related” is published and understood in advance. Teachers and pupils would know what success looks like. Schools could work towards it transparently. And if, nationally, we want to raise standards, we can do that openly by increasing the level of challenge over time.

This would be a shift towards a more criterion-referenced model: pupils are measured against a defined standard, not against how others happened to perform in that particular year.

There’s another issue underneath: an overloaded primary curriculum

Even with better assessment, we should also be honest about the curriculum itself. Years ago, a Year 6 colleague told me they felt disheartened when they looked at what many pupils would be taught again in Year 7: much of it appeared to be a repeat of primary content.

That conversation stuck with me. Primary colleagues work incredibly hard. Children make real progress. But when we step back and look at what is expected, and then compare it to what is revisited immediately afterwards, it raises a wider systemic question: is the primary mathematics curriculum overloaded?

This is why I’m hopeful that curriculum review work will address issues of breadth, coherence, and what “secure” should realistically mean at the end of primary school. Early indications suggest some movement in this direction.

However, even if the curriculum is improved, we will still have a problem if the assessment system remains unchanged. If we keep a model where thresholds are set in a way that effectively ensures some pupils will not be judged “age-related”, then we will still be stuck with the same contradiction.

Conclusion: we need assessment that matches our ambition

To return to my original point: yes, every child can master mathematics. But in our current system, not every child can be assessed as having mastered it.

That is a real shame, especially given the great work happening across mathematics education in this country. If teaching for mastery is our direction of travel—and I believe it should be—then our assessment and accountability systems need to align with that vision, not undermine it.

Thank you for reading, and for bearing with me on my winding journey.

Malcolm WatsonTeaching for Mastery Specialist, Cambridge Maths Hub

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