Ever since I started teaching I have felt guilty about differentiation. I can't remember much about behaviour management from my training, but I do remember that differentiated teaching strategies came up a lot. Since then, I have periodically marvelled at those super teachers who seem to have it sorted.
But perhaps my feelings of guilt are unnecessary. If we take differentiation to mean asking different students to complete different activities in the same class, then evidence is starting to emerge that it may not be the holy grail of teaching after all.
This may strike you as odd, and with good reason. According to researchers from the University of Manchester, students starting secondary school typically display a six-year spread in mathematical ability. It stands to reason that we cannot teach all these children the same things. Is it not better to tailor the teaching to what each child needs? We can achieve this by grouping students within the classroom and giving different tasks to the different groups.
However, this comes at a cost. If we still have only one teacher in the room, that teacher will have to split their teaching between the groups. In a one-hour lesson with five groups, that's just 12 minutes each. And that's before we factor in time for creating the groups and managing behaviour.
And what will the students do between periods of direct teacher input? Will they learn from each other, reinforce each other's misconceptions or take the opportunity to coast? Perhaps the cost of less targeted teaching is outweighed by the benefit of increased whole-class instruction.
This should be an ideal conundrum to test through educational research. However, a fundamental tenet of scientific research is that you change only one thing at a time. Pitting whole-class instruction against differentiated teaching changes at least two things: the format of the lesson and the tasks the students have to complete. So it's a bit of a problem.
Agreement about what we are differentiating for isn't universal, either. Devotees of the practice often accept ideas such as learning styles or multiple intelligences and say we should differentiate accordingly. This clouds the matter further because such theories have been widely evaluated and found wanting.
Nevertheless, attempts have been made to test the effect of differentiation and the results are distinctly underwhelming.
A research team in the US conducted a classic "horse-race" study, testing three conditions: differentiated teaching, standard teaching with differentiated assessment and an undifferentiated approach. Despite running for a number of years, the study found little evidence to support differentiated instruction. The results were largely inconclusive, with the association between teaching approach and improvements in performance generally found to be weak.
The researchers captured a lot of qualitative information through interviews and suggested that a major reason for the results not being stronger was because differentiation was often poorly implemented. They also cited resistance from teachers and school leaders as a factor.
I sympathise with those reluctant teachers. One of the reasons I have a troubled relationship with differentiation is because it is so hard. Instead of one resource, it requires teachers to create four or five. When you are teaching several lessons a day, you begin to understand the difficulty.
And you have to wonder just how well matched resources end up being to students' needs. Is it sometimes a case of hurriedly grabbing something that seems good enough, rather than truly tailoring it to the task?
International comparisons come to similar conclusions. The Organisation for Economic Cooperation and Development recently conducted survey of teachers around the world (bit.lyOECDTalis2013). One question asked: "How often do you give different work to the students who have difficulty learning andor those who can advance faster?" The nations performing better in the Programme for International Student Assessment (Pisa) tended to report doing this less often.
A possible explanation may be gleaned from a small study by David Reynolds and Zhenzhen Miao of the University of Southampton (bit.lyChinaMaths). They observed Chinese and English maths lessons and found that the Chinese students performed better than their English peers in maths assessments both at the start and the end of the study. They also found that whole-class, interactive teaching was being used 72 per cent of the time in the China and only 24 per cent of the time in England. Differentiated instruction necessarily turns us away from whole-class interactive teaching and yet this may well be one of our most effective teaching strategies.
And what about expectations? Categorising a child and placing her in a particular group within a class may lead to lower teacher or student expectations. Perhaps all children could succeed on the one task if given the chance.
A study of primary teachers in the US found that students placed in the lowest in-class groups spent more time "involved in non-instructional activities and [were] less likely to be asked critical comprehension questions".
This is the same issue that affects the most common alternative to differentiation: placing students into ability groups or sets. The consensus is that this approach may be beneficial for some high-performing students but it is often detrimental to those in the lowest groups. How much this is a result of the setting or the tendency to assign less effective teachers to lower groups is unclear. An interesting study by King's College London intends to test this idea over the next few years.
So what should we conclude? There is no overwhelming evidence to support efforts to teach multiple lessons within one class. Given the work that differentiation involves, I suggest it is probably better to look for other ways to cater to different abilities; a kind of "differentiation-lite", perhaps.
This could involve a large component of whole-class teaching but with some students who already understand the concepts working independently as the same ideas are reinforced with others. I find targeted verbal questioning useful too, but it's better if it is planned in advance. And I often give students the opportunity to come to the front and explain the concepts that they have grasped well - it provides an alternative explanation to mine and I am there to clarify any misconceptions.
In short, we need a more pragmatic approach, one that recognises student difference without throwing the whole-class baby out with the bathwater.
Greg Ashman is a teacher at Ballarat Clarendon College in Victoria, Australia. Find him on Twitter @greg_ashman
Ryan, J and Williams, J (2007) Children's Mathematics 4-15: Learning from errors and misconceptions (Open University Press)
Tomlinson, C A, Brighton, C, Hertberg, H et al (2003) "Differentiating instruction in response to student readiness, interest, and learning profile in academically diverse classrooms: a review of literature", Journal for the Education of the Gifted 272-3: 119-145
Chorzempa, B F and Graham, S (2006) "Primary-grade teachers' use of within-class ability grouping in reading", Journal of Educational Psychology 983: 529-541