Half the vices which the world condemns most loudly have seeds of good in them and require moderated use rather than total abstinence. Samuel Butler

According to a recent TES article, Professor John Hattie, “one of the world’s most widely quoted education academics,” has been telling teachers that it’s a ‘sin’ to tell teachers how to teach. I’m sure the irony went unnoticed.

Is he right?

He apparently he said

80 per cent of what happens in the classroom remains unseen and unheard by teachers – only the pupils are aware of it. “So why would I give a damn about reflective teaching?” he said. “I don’t want to think about the 20 per cent we see. I want to think about the 80 per cent that goes on that we don’t see.”

These kinds of percentages seem obviously spurious. I’m 87% sure we can never know the exact quantity of what a teacher or pupil is aware of. I’m more than happy to agree that teachers are largely unaware of what goes on in classrooms, but then, so are pupils. The very premise of ‘visible learning’ is more than a little bit silly as learning is, by its very nature, invisible. All we see can see is pupils’ performances from which we can only infer what they might still know later and elsewhere.

Hattie believes we can make learning visible through testing.

The role of testing, he believes, is not to test pupils’ knowledge: it is to test whether teaching is effective. “I should be learning something about what impact I had, who I had an impact on,” Professor Hattie said. “What I’ve taught well and what I haven’t taught well… Because tests don’t tell kids about how much they’ve learnt. Kids are very, very good at predicting how well they’ll do in a test.”

The role of testing should be to build pupils’ knowledge, not to check what they know. retrieval practice is widely agreed to be one of the most robust ways of increasing the flexibility and durability of what students know. This is the testing effect. Any test conducted in the classroom and marked by teachers will, to a greater or lesser extent, be unreliable and invalid. As such it will tell a teacher little useful beyond the fact that students make obvious and predictable misconceptions, and we don’t really need to test to tell us that.

I’d also say he’s spectacularly wrong in claiming that students are good at predicting how well they’re likely to do in a test. Most students are novices – they don’t yet know much about the subject they’re studying. Not only do they not know much, they’re unlikely to know the value of what they do know or have much of an idea about the extent of their ignorance. As such they’re likely to suffer from the Dunning-Kruger effect and over-estimate the extent of their expertise. All of this creates a sense of familiarity with subject content which leads to the illusion of knowledge. The reason tests are so good at building students’ knowledge is because they revealing surprising information about what is actually known as opposed to what we think we know. Added to that, our ability to accurately self-report on anything is weak at best.

Teaching is an interesting domain of expertise because our intuition improves in some areas but not in others. When it comes to classroom management, we get excellent feedback on the quality of our decisions; students will take every opportunity to politely point out if we get things wrong. But when it comes the quality of our instruction we tend not to ever get useful feedback on what works. Worse than that, we are deceived as to the most effective ways to get students’ to retain and transfer knowledge because all we usually see is students’ performance at the point of instruction which is usually a poor predictor of what will happen later and elsewhere.

Delayed tests do provide better information about whether students are learning and may give us some insight into whether our teaching is effective. The problem is, how can we apply pupils’ performance on a test taken a month after instruction to how we ought to have taught? We have to take the connections between teaching and learning largely on faith. Should we expect teachers to rely on their own intuitive ability to translate test results into improved instruction, or should we intervene to help them get better? Research tells us that certain practices provide the best bets and telling teachers how to align their practice to what is known to have been most effective in the past may actually be the most useful thing we can do.

Of course, bias and preference will get in the way and Hattie may well be right that all we do is tell other teachers how to teach like us. But we can take steps to become aware of this likelihood and guard against it. Where Hattie is right he where he says,

Foster that interdependence between staff, so it’s OK to say, ‘I’m struggling with these kids – can you help me?’… But I see staff sitting at the same table in the staffroom, working alone. It really is this notion of how you build this trust, both in the classroom and in the staffroom.

Schools often actively undermine the growth mindset and we would do well to consider what we can learn from the aviation industry.