Here’s a question for you: what does teacher subject knowledge have to do with raising pupils’ “cultural capital”? Quite a lot, according to my own research.

All teachers at my school conduct empirical research each year as part of our performance management. Last year, I discovered that, by using high-level subject knowledge to move beyond a scheme of work at critical points, I was able to level the playing field for disadvantaged students who have less access to “cultural capital” (Pierre Bourdieu’s term for the educational and cultural advantages of a middle-class upbringing) at home.

I found, though, that the value of subject knowledge goes far beyond cultural capital. Put simply, students learn best when taught by teachers with high subject knowledge.

1. Deliver challenging content

Education charity the Sutton Trust’s What Makes Great Teaching report (2014) found that the most effective teachers have deep knowledge of the subject they teach. And with an increasingly “knowledge-led” curriculum, this deep subject knowledge is important in ensuring that teachers are able to deliver challenging content. But how can you make the most of your subject knowledge in your classroom? What does the research have to say about that? After reading the Sutton Trust’s report, I decided to try to incorporate some of the findings of studies about deep subject knowledge into my lessons.

Where to begin? My first step was to read around the subject further to develop my understanding of how to improve outcomes. I came across research by John Hattie, which suggested that even more important than subject knowledge itself is a teacher’s ability to use and integrate that knowledge in their teaching. In Visible Learning for Teachers (2011), he explains that expert teachers are able to make use of subject knowledge to organise curriculum content more effectively, thereby aiding students’ understanding. Linking to this, I revisited David Tripp’s concept of “critical incidents”, where he encourages teachers to reflect critically on key pedagogical events.

Armed with this understanding, the next step was to develop a strategy for using high-level subject knowledge to improve outcomes. Guided by the existing research, I developed my own concept of “critical moments for subject knowledge” - times when we do not necessarily expect to teach a particular concept but use an event or discussion in a lesson to stretch students beyond the curriculum. I realised that I would have to make sure I was reading and revising degree-level knowledge for the texts I was teaching. So, I went back to what I would have done as an undergraduate and read as widely as possible, then used my revised knowledge at critical moments in my lessons.

For example, when teaching Macbeth to Year 8, we explicitly examined the play using a feminist literary reading (teaching critical theory is normally left to GCSE or A level). With Year 7, I discussed non-sequiturs and satire within our “writing to argue” topic, rather than stopping at the usual key stage 3 level of rhetorical questions and puns. When reading our fiction text, we explored analepsis, intertextuality and reader-response theory. None of this was in the curriculum plan but all of it might come in handy for students in the future.

2. Stretch their subject knowledge

Even more importantly, teaching such high-level knowledge encourages intellectual enthusiasm and helps to emphasise the innate value of high-level vocabulary and knowledge. While still scaffolding lessons for students where necessary, I tried to imagine I was teaching a degree-level class for any year group, using any opportunity possible to stretch their subject knowledge.

Crucially, if I had not possessed good subject knowledge, I would not have recognised the critical moments to weave these concepts into my lessons. Inspired by Hattie’s research that the best teachers use subject knowledge to organise curriculum content effectively, I ensured that whenever I had spontaneously introduced new knowledge, I made a note of this and consciously linked back to it later in order to embed the learning.

So, what was the impact? Well, first, I noticed students enjoyed the increased level of challenge, proudly using sophisticated terminology and degree-level knowledge in their verbal and written responses. They particularly loved it when I used phrases such as, “I didn’t learn this until my master’s degree/A levels/last week, but…” (everyone loves feeling clever, after all).

Second, progress and outcomes across the board were higher - although it’s important to bear in mind that this was just one study in my own classroom, over one year, so generalisations applied to other contexts aren’t yet possible.

What were the challenges of including degree-level knowledge? I found that it does require an investment of time on the teacher’s part to develop their subject knowledge, whether that’s through reading, watching documentaries, attending conferences or even just watching YouTube videos. Hopefully, though, for those who enjoy their subject, this should be a pleasure rather than a chore.

Encourage your head of department to subscribe to a subject journal or to buy key subject-related texts to discuss at department meetings, to help foster a whole-team enthusiasm for subject knowledge.

This year, we built in opportunities as a department for teachers to share developments in their subject knowledge, and have developed vocabulary and terminology banks for staff to access, helping them to use these at critical moments.

3. Introduce advanced concepts

Another difficulty is around introducing advanced concepts to older or less self-motivated students, who aren’t used to being pushed and will occasionally sigh, “but do we need to know this for our GCSE?” To encourage children to aim high, we need to embed rich, deep subject knowledge from the beginning of Year 7 to ensure that students do not develop a mindset of low expectations.

Applying this research in your own context can definitely be a challenge. So, in summary, here are my top tips for incorporating high-level subject knowledge in your lessons:

* Have the confidence to recognise critical moments in your teaching and occasionally diverge from the lesson plan.

* Keep developing and extending your own subject knowledge and, most importantly, use this in your teaching.

* Don’t shy away from adapting A-level or degree-level knowledge for Year 7s or even primary level.

* Recognise where your critical moments have occurred and link back to this knowledge in subsequent lessons.

Megan Mansworth is leader of research at Mowbray Education Trust, a literacy coordinator and an English teacher