Didau v Wiliam: formally assessing the heavyweight contest of the year so far

What struck me recently in the debate between David Didau and Dylan Wiliam was the latters view that actually the two were discussing something other, or rather that they were discussing the same thing but not, if you get my drift.

Alright maybe you don’t, I’m working my way through this, you’ll have to be patient. David Didau points to the difference here:

Some of these strategies contain real merit if undertaken thoughtfully, but there’s a very real danger that the ‘big idea’ of AfL might be fundamentally, and fatally, flawed. AfL is predicated on the assumption that you can assess what pupils have learned in an individual lesson, and then adjust future teaching based on this assumption.

If nothing has changed in long-term memory, nothing has been learned.

The implication is clear:

 There’s no meaningful way to assess what pupils have learned during the lesson in which they are supposed to learning it.

Dylan Wiliam describes the problem thus:

This is an extraordinarily complex task, because we are trying to construct models of what is happening in a students’ mind when this is not directly observable.

In other words you cannot easily know that, which is not observable. Dylan Wiliam therefore makes the point in this paragraph:

This is why my definition of formative assessment does not require that the inferences we make from the evidence of student achievement actually improve student learning— learning is too complex and messy for this ever to be certain. What we can do is increase the odds that we are making the right decision on the basis of evidence rather than hunch.

Of course, at this point my own hunch would be that this is really another epistemic argument about what constitutes evidence. For example; if you cannot directly infer learning then how can you make a decision on the basis of evidence? More to the point if you cannot infer learning, what is the difference between evidence and simply a hunch?

Wiliam quotes Von Glaserfeld:

In the one case as in the other, the best that can be achieved is a model that remains viable within the range of available experience.” (von Glasersfeld, 1987 p. 13)

The answer offered by Von Glaserfeld is that evidence can only be “best fit” or as Dylan Wiliam describes it:

…..teaching will be better if the teacher bases their decisions about what to do next on a reasonably accurate model of the students’ thinking.

This is achieved by a range of assessment methods, not “just questioning”. Of course I agree, however, it does suggest something about “evidence”, you have to consider it in a way that is much more widely stated than that offered by direct observation.

On the other hand David Didau comes at the issue from the opposite direction:

…why not spend time deconstructing exemplars and modelling the expert processes we would use to complete a task?

We are now looking at the world from the other epistemic perspective, that of, the expert teaching the non expert how to be an expert. In this case, it seems to me that there is an assumption that there is only one way to achieve a task. It removes the agency from the learner. The notion that you can model an expert process for learning also implies  something about the kind of learning that is trying to be achieved, and it also tends to suggest a highly defined relationship between the model and learning itself. Here David seems to me to be raising more questions than he is answering.

Didau criticises Wiliams’ constructivist approach (for the want of  a better word):

Each of these are about putting the child at the centre of the classroom and moving the teacher to the side. These kinds of techniques have gained a great deal of traction in classrooms. But often at the cost of efficiency. There is always an opportunity cost: If I ask pupils to spend a lesson working things out in groups, that is a lesson I cannot spend teaching them.

The question though, is that, having established that learning is a tricky beast you do wonder at the use of language such as “opportunity cost”. I mean if you cannot easily know learning you cannot easily know the “opportunity cost” of it.

David Didau says:

If we force children to work cooperatively all the time they will never know enough to produce thinking or work of any quality. Cooperative learning (or ‘independent learning’ as it’s often called) certainly has a place, but it should come after careful explanation and modelling.

This does conjure images of learners being forced at gun point to work together; “we have ways of making you co-operate”, so, of course they need careful explanation and modelling. But hang on a second haven’t we just established that we cannot know what an individual learner is learning?

The question therefore is, careful modelling of what? And what will the learner learn from that careful modelling. It just seems to me that we have some epistemic confusion here. On the one hand we have the critique of Wiliams based on the fact that we cannot know what learning is; several paragraphs later we are carefully explaining and modelling it.

Didau admits:

Of course, I may well be wrong

So might I

I do know that there are hugely powerful cognitive biases at work that will protect us from admitting that our belief systems might be wrong.

Well quite.

Wiliam considers that this is an issue about how Government interprets pedagogy, in this case AFL:

David has certainly provided an effective critique of “assessment for learning” as enacted in government policy, and in many schools

And to some extent he is right because government has the same problem. Where’s the evidence? Or rather where’s the evidence of learning. How can you have an accountability system based on observations, if you are admitting that in fact observations are a waste of time.

The whole education system is based upon the need of a hierarchy of people to evidence expertise; whether it be the inspectors who can grade sessions; 1,2,3 or 4, or the advanced practitioners who can show…well less advanced teachers, how to assess by asking questions; “sorry but closed questions are just no no at that point?”, “have you considered an open question here?”.

So, of course, it’s an uncomfortable admission that actually what really matters is what Dylan Wiliam describes as, the “teacher – learner” relationship. There are a great many people out there for whom that admission, is simply not one that they want to accept, for obvious reasons.  Evidence becomes, whatever is convenient for us to believe, at any given time. David Didau calls it cognitive bias, some  would call it convenient truths, either way it seems that being aware of it does not necessarily protect us from being susceptible to it.

My own view is that this is not a debate about government or the difference between research and practice, but a debate about how we come to know things (epistemology). The key question is, what constitutes evidence in a domain where the scientific (or medical model) based, as it is, largely on replicable observable events is not really appropriate. What differentiates Didau and Wiliam, in this case, it seems to me is a fundamental difference of opinion on how to derive a knowledge of the social world.


Tip of the hat to both David Didau and Dylan Wiliam. A brilliant bit of BLOGGING from both.


3 thoughts on “Didau v Wiliam: formally assessing the heavyweight contest of the year so far

  1. You share interesting things here. I think that your website can go viral easily, but
    you must give it initial boost and i know how
    to do it, just type in google for – mundillo traffic increase go viral

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s