According to Teacher Tapp, 56% of teachers reckon their schools start GCSE courses at some point during Year 9.

Part of the justification for this approach is that Key Stage 3 has sometimes had a reputation for being a bit of an intellectual wasteland. In 2015, Ofsted publish a report entitled Key Stage 3: The wasted years? which argued that “in too many schools the quality of teaching and the rate of pupils’ progress and achievement were not good enough.” Clearly, doing something purposeful is an improvement over three years of colouring in, poster making and young adult class readers.

The other argument is that there is so much content that needs to be taught in order to adequately prepare students for the new GCSE specifications that then only way it’s possible is to begin a year earlier. Certainly, when it comes to subjects like triple science I have some sympathy; there really is a lot to get through. Also, the curriculum allocation given to some option subjects has been increasingly squeezed in order to give KS4 students ever greater time to study English and maths (arguably two of the subjects that need the extra time least). Teaching a subject like history in less than 5 hours a fortnight will be a challenge.

Now of course it would be incorrect to say a three-year KS3 is always better than a three-year KS4; you can do anything badly or well. But the fundamental principle here is that KS3 encourages breath – both within subjects and across the curriculum as a whole – whereas as KS4 necessitates studying subjects in increasing depth.

The way for forward is to identify the underpinning conceptual lens through which subject knowledge can be viewed. These will be different for every subject. In history conceptual ways of seeing include ‘narrative’ and ‘causation’. Cause and effect’ might also be a fundamental concept in geography but it will be different; instead thinking about how different historical events might have impacted on each other, students need to think about how different effects change the planet and how the earth effects how people live in it. ‘Narrative’ is also an important concept in English literature, but whereas in history students learn how stories are created to explain historical events, in English they need to see how writers create an internal reality by sequencing events in ways other than just the chronological. These ways of seeing the world can only really be taught be viewing as much of the subject domain through them as possible.

It’s perfectly possible to teach subjects like English and history in a way that leapfrogs from one area of detailed study to another omitting everything that connects them. When teaching A level, I was regularly struck by the fact that students would have performed well at GCSE whilst knowing only 2 or 3 plays or novels and a handful of poems. They would often know nothing about English literature.

Studying 3 or 4 topics in depth will mean there is little time to see how each area connects, but when we focus on breadth, we can introduce students to as much of our subject domains as possible. As each each new aspect of our subject is introduced, students build up increasingly robust, interconnected schema. The more they know, the easier they will find it to integrate each new detail. (More on how this process works here.) If we take the time to remind students of our subject’s conceptual understandings each time we introduce more breadth, the more quickly and easily they will add to their schema and, when we eventually focus on teaching certain topics in greater depth, the breadth of their schema will make it easier for them to acquire new details and layers of difficulty.

Failure to think like this runs counter to the interests of social justice. If we neglect breadth in favour of depth then those children who come to school knowing more will benefit. By ensuring all children know more about our subjects we advantage the least advantaged.

If we prioritise depth over breadth then students who succeed in our subjects are more likely to do so despite not because of the curriculum we teach.