Does Teachers’ Subject Knowledge Matter?
By: Alice Germain
Tags: Science Education, Education, Pgce

Beyond the issue of the physics-with-maths teacher training discussed in my previous post, there is a fundamental question underlying the teaching in schools of the three sciences by a same teacher up to GSCE (year 11), namely, How important is subject knowledge for a teacher? Andrew, my university mentor, mentioned during one science session at university that this question has been recently the object of a big debate within the education science community. He said he had no clear answer to this, but all he could say is that he had noticed that PGCE students holding a Ph.D. are the most difficult to train.

Let’s pause here for a minute to analyse Andrew’s statement, and let’s try to focus on one of the objectives of science education, namely the production of responsible citizens who can make informed decisions for themselves and critically read science articles — where ‘critically’ means that they won’t believe any ‘scientific’ claim and will be able, for instance, to distinguish between mere correlation and causation. A graph showing the world global temperature as a function of the number of pirates is a typical example used to illustrate the difference between both. The graph clearly shows a negative correlation between the number of pirates and the global temperature (the temperature increases when the number of pirates decreases). Does it mean that the progressive disappearance of pirates over time caused the global rise in temperature on our planet? Or that pirates disappeared because of the temperature rise? To see here a causation is obviously absurd. It is indeed important that people don’t confuse correlation and causation, otherwise they may misunderstand some ‘scientific’ claims. Imagine for example an article about a ‘scientific’ study claiming that e.g. if you vote for the Conservative Party, you live longer (I’ve just made it up, but it seems plausible to find a correlation here, because probably on average people who vote for the Conservative Party are wealthier and so have access to better life conditions and better health care, and so on average live longer). Some — uneducated — people may then decide to vote for the Conservative Party because ‘it makes you live longer’.

Let’s come back to Andrew’s statement. In the context of the ‘big debate’ on the importance (or not) of subject knowledge for a ‘good’ teacher, PGCE students who have a Ph.D. can be considered as the ones with stronger subject knowledge. The other part of the statement (that they are the most difficult to train) implies that they are not ‘naturally’ good teachers. So, according to Andrew, there would be a correlation between subject knowledge and easiness to be trained as a teacher. As Daniel Kahneman showed in his book “Thinking, fast and slow”[1], humans easily jump to conclusions without having robust evidence. In the present context, the correlation observed by Andrew would be easily interpreted as ‘someone with strong subject knowledge — e.g. with a Ph.D. — makes a less good teacher’. In that way, the alleged correlation has become causation. It is not what Andrew said, and I cannot pretend this is what he wanted to say, but I am pretty sure that this is the conclusion that many of us will have jumped to. For Andrew’s statement to be an objective contribution to the debate, he should have explored alternative explanations in relation to the observed correlation. For instance, the fact that PGCE students holding a Ph.D. are more difficult to train as teachers could be simply because they are older and have gathered work experience during their Ph.D., and so are less likely to do what they are told without questioning the soundness of it, or because their Ph.D. work taught them to think more critically… I don’t have the answer. I am just saying there is no scientific evidence that good subject knowledge is detrimental to becoming a good teacher.

Many science teachers seem to think that teaching the three sciences is not so bad after all. Some of them, as discussed in my previous post, even claim that they teach better their non-speciality subjects. It is interesting to note that, in private and grammar schools, science teachers generally teach only their specialist subject. After having discussed this with Andrew, it appears that a barrier in comprehensive schools to science teachers teaching only their speciality is that they would teach all their classes up to year 11 only one lesson per week. And this poses a behaviour issue in schools with challenging children, where teachers need to know their students well and see them often to have efficient behaviour routines. In private and grammar schools, children are usually better behaved and more motivated, so that behaviour issues don’t hinder subject teaching. Interestingly, nobody in private or grammar schools seems to claim that teaching subjects you have no idea of (and maybe don’t want to teach) is actually positive for your students. But wouldn’t it be possible, with some creativity and imagination, to find another way of organising science classes and solve this one-lesson-per-week issue?

Besides the debate shaking the education community, I have to mention that subject knowledge, along with pedagogy knowledge, is one of the teacher standards (number 4 — the teachers’ standards “set the minimum requirements for teachers’ practice and conduct”.[2]) So, reader, please be reassured, to become a qualified teacher, one has to bring evidence of one’s subject knowledge. It often starts with having a degree in the subject you want to teach. But not always — and as we’ve just seen, for science teachers there is at least one subject that they haven’t studied after A-level (or sometimes even after their GCSE). As a PGCE student, you could expect to go through the curriculum in the three sciences during the university sessions, study the common misconceptions you can expect from your students — and at the same time get rid of your own — and learn how to teach the three subjects properly. But, no. Regarding your own subject knowledge, you are expected to self-assess your shortcomings — and consequently study to remedy them. There are indeed a few sessions on how to teach some of the main topics of the curriculum — but in your speciality! So, at the end of the training you may have learned by yourself what you have to teach your students in your non-speciality subjects, but that’s it. However, as subject knowledge is one of the teacher standards, it is assessed when you are observed teaching. I must say that I was surprised to be praised for my subject knowledge after lessons where I didn’t have the feeling to have used my knowledge beyond the curriculum. I wondered whether it was because the observing teacher still could tell that I had the big picture and I knew what I was talking about, or whether it was just an easy way to say something positive.

Meanwhile, I soon realised that some of my non-physicist colleagues at university had serious shortcomings in physics. For instance, during one science session at university, I was in a group with Carissa, a young biologist, along with another physicist and a chemist. We had to go through some practical activities that were proposed to year 7 children in the framework of a project called “let’s think”[3]. One of the activities was to put several objects of different sizes in water and see whether they float or sink. Carissa exhibited childish excitement and surprise when she realised that some of the bigger objects would float while some of the smaller ones would sink. The other physicist and I looked at each other, aghast. This absence of knowledge and understanding of the basic concept of density and the explanation of why some objects float or sink surprised me even more because we had already had an ‘inquiry activity’ on floating in a previous session. For that inquiry, we had to put an orange in water, observe that the orange would float, then peel it little by little and observe that at some point the orange would sink. Of course, following the radical constructivism teaching theory, our teachers didn’t remind us of the theory behind the experiment, whether or not they expected that we knew about it — if not, I guess we were supposed to find out by ourselves. Jackie, Carissa’s tutor, had furthermore mentioned that she observed Carissa teach in her school this orange inquiry lesson. So, not only did she not know why an object floats or sinks, but she even taught a lesson on that very same topic without wondering what the explanation is. I would like to know what the children could possibly learn from their investigation if the teacher could not even guide them towards the right explanation. Maybe that’s the absolute dream of constructivists? Maybe we could even go a step further and leave the children to their own devices. If someone could definitively prove that children learn better without teachers, surely that would be the perfect solution to the current teacher shortage.

Carissa arrived in my first placement’s school for her second placement while I was in my second placement school, which lasted only 4 weeks for me. When I came back, my mentor explained to me that they had just hired Carissa. “We are a very strong science department,” he said, “but we always need good people”. It is not clear whether they had appreciated the scale of her deficiencies — I may give them the benefit of the doubt here. I hope this story is not representative of what happens in schools. However, I heard similar stories of young teachers being hired in spite of their obvious lack of subject knowledge uncovered during the interview lesson.

When you come from a country where the selection process of future teachers is essentially based on their subject knowledge, such stories sound incredible. While I think it is a mistake to believe that it is sufficient to be good at a subject to become a good teacher in this subject, it is simply another — and as big — mistake to consider this is not a necessary condition.

As Jerome Bruner said[4], “When we try to get a child to understand a concept, leaving aside now the question of whether he can ‘say’ it, the first and most important problem, obviously, is that we as expositors understand it ourselves. I apologise for making such a banal point, but I must do so, for I think that its implications are not well understood. To understand something well is to sense wherein it is simple, wherein it is an instance of a simpler, general case. In the main, to understand something is to sense the simpler structure that underlies a range of instances.”

[1] Kahneman, D. (2011). Thinking, fast and slow. New York: Farrar, Straus and Giroux.

[2] https://www.gov.uk/government/publications/teachers-standards

[3] http://www.letsthink.org.uk/

[4] On learning mathematics, The Mathematics Teacher (1960) vol. 53, N 8 pp 610–619