When we speak of differentiation in education/teaching, we need to differentiate (pun intended) between divergent and convergent differentiation. Both are based on the individualisation principle which holds that every learner/student learns at their own pace, has their own particular aptitude for learning, and that these differences should be taken into account when teaching and assessing. Students differ in aptitude, prior knowledge, language proficiency, learning pace, interests, background and culture, motivation, ability to concentrate and so forth. We, as teachers, have to take that into account to provide sufficiently differentiated support to ensure that individual differences in learning outcomes are minimal.

But when we do this, a problem lurks in our good intentions, namely the Matthew Effect. According to Wikipedia, the full name is the Matthew Effect of Accumulated Advantage and it “is the tendency of individuals to accrue social or economic success in proportion to their initial level of popularity, friends, and wealth”. You sometimes hear it as ‘the rich get richer and the poor get poorer’”. Coined by sociologists Robert K. Merton and Harriet Zuckerman it takes its name from a loose interpretation of the Parable of the Talents in the Gospel of Matthew.

For to every one who has will more be given, and he will have abundance; but from him who has not, even what he has will be taken away.
— Matthew 25:29

In education, the term was first used by Keith Stanovich to describe how new readers acquire the skills to read. Based upon his observations, he noted that early success in learning to read usually leads to later successes in reading as the learner grows, while failing to learn to read before the third or fourth year of schooling can lead to lifelong problems in learning new skills. In the words of Stanovich[1]:

Slow reading acquisition has cognitive, behavioral, and motivational consequences that slow the development of other cognitive skills and inhibit performance on many academic tasks. In short, as reading develops, other cognitive processes linked to it track the level of reading skill. Knowledge bases that are in reciprocal relationships with reading are also inhibited from further development. The longer this developmental sequence is allowed to continue, the more generalized the deficits will become, seeping into more and more areas of cognition and behavior. Or to put it more simply – and sadly – in the words of a tearful nine-year-old, already falling frustratingly behind his peers in reading progress, “Reading affects everything you do.”

Education has the obligation to reduce this gap; thus, to counteract the Matthew effect. But a problem here is how schools often deal with differences between students in a heterogeneous classroom. In such classrooms, students are often divided into (at least) three groups: weak/slow students, average students, and strong/fast students. The teacher then sets goals for each of the three groups and teaches accordingly. And herein lies the problem. This divergence has the pernicious and adverse side effect of increasing the Matthew Effect as can be seen in the following figure:

Divergent differentiation is a form of differentiation in which the students are addressed and taught at their level in terms of instruction and processing, which creates increasingly large differences in level. For example, in divergent differentiation, teachers offer students different learning content or have students work towards different goals. They set the bar lower for the weaker students and the bar higher for stronger students. In short: the learning objectives are not the same for all students and, thus the different groups of students learn different things. The slower/weaker students learn not only less but also learn other things than the quicker/stronger students. And as anyone who has read Don (E.D.) Hirsch Jr. knows[2], the consequence of this divergence is a loss of shared knowledge that is necessary for people to work together, understand one another, and make coherent, informed decisions.

But the goal of education, and thus of your teaching, should be that all students achieve the same basic level of mastery, so that all children have the same knowledge base. And to achieve this we need convergent differentiation. Convergent differentiation is a form of differentiation in which you always want to keep the entire group together in terms of what they learn, i.e., learning material. Convergence here means ‘coming together’. The teacher tries to get all children in the class to achieve the same set of goals. [Note: Someone apparently read this and thought that I felt that we should ‘concede’ to the slowest learner. I thought I was clear that what we wanted students to ‘minimally’ learn/achieve wasn’t norm-based but rather criterion-based. Choose the criterion level and have everyone reach it!] The emphasis is then on improving the performance of weaker students, so that these students can also achieve the minimum goals. The goals aren’t different, but the instructional techniques used are (see the figure below). Convergent differentiation is working towards equal goals through different instructional approaches. At each nodule in the figure, all of the students have achieved the same sub-goals. Of course, along the way, the children will eventually learn some different things, but the crux of the matter is that everyone reaches/masters the set criterion goals.

And how do we do this? First we must choose common goal/proficiency level. Then we need to observe our students carefully and not jump to conclusions about what they can and can’t do. Finally, we need to determine the most appropriate instructional approach to use including media, step size, pace of instruction, type and amount of support and guidance, type of feedback given and so forth. In this way you help ‘educate a citizen’!

As rapper Judakiss ‘sang’: We’re all in the same game, just different levels. Dealing with the same hell, just different devils.”

[1] Adams, M. J. (1990). Beginning to read: Thinking and learning about print. MIT Press. pp. 59–60.

[2] How to Educate a Citizen: The Power of Shared Knowledge to Unify a Nation