Some swear four is optimal. Others can’t fathom why you would ever have any fewer than six. And then there are those who base their decision purely on the size of the tables in the classroom.

So, who is right? When it comes to group work, does it really matter how many pupils are in each group? Or is picking the number by table size as good a method as any?

It’s a question few teachers will have had to ponder in the past few months, unless they attempted digital group work via video-conferencing or collaboration tools. But, as pupils trickle back into schools, and with an eye on a relaxation of social distancing measures in the future, reintroducing group work will be something many teachers will consider for next year - particularly due to children’s loss of social time.

So, what should group sizes be if we want to maximise learning? Robert Slavin, director of the Center for Research and Reform in Education at Johns Hopkins University, in Maryland, US, is well known for his work on cooperative learning, which includes a chapter titled “What makes group work work?” for the Organisation for Economic Cooperation and Development’s 2010 book The Nature of Learning.

“For cooperative group work, groups of four are the norm,” Slavin says - adding that he has “never heard of groups of six or eight for ordinary classroom use”.

And if a teacher reading this is partial to a group of eight? “The problem is that, in such large groups, shy or uncertain students are likely to say little or nothing, and may not participate,” he says.

But Slavin isn’t stating that the norm is necessarily always correct. Indeed, Ed Baines, a senior lecturer in the psychology of education at the UCL Institute of Education, who has published widely on the topic of collaboration in the classroom, explains that group size is much more complex than many will have realised.

“There are features of the group context that need to be considered - like group composition, group stability, space and seating arrangements and resources,” he says.

And that’s not all. Baines says teachers will also need to think about the nature of the task and the children involved - their experience or age, their social and communication skills, and how they, as the educator, will support the group activity.

“It is helpful to think about group working activity as involving two main strands of activity that group members have to engage with,” he adds. “First there is the doing of the substantive task of the work set. The second main strand is the challenge of actually working together in a constructive way that enables the group to do the substantive task.”

He believes the second strand is usually overlooked, with pupils’ skills in working together “often taken for granted”.

“Working together with others in productive ways is actually very demanding, even for many adults,” he says. “In order for children to work productively in groups, they need to have had a chance to develop the skills and qualities that are involved in productive team working.”

Considering all of the above, it seems likely that teachers need to build different group sizes dependent on myriad other factors: isn’t that going to make planning for group work incredibly difficult?

It’s certainly going to need careful thought, says Peter Kutnick, emeritus professor in the School of Education, Communication and Society at King’s College London, who has been researching effective group work in classrooms for two decades.

“There is no simple answer to [questions about the] ideal size for a within-class group,” he says, adding that there are “various types of ‘classroom learning’ scenarios that involve different types and sizes of groups”.

Faced with such complexity, will teachers bother doing group work at all? The evidence on collaborative work certainly suggests it is worthwhile: it tends to have a positive impact. And, helpfully, the academics do have some rough rules to guide school staff, based on the research.

“Cognitively stimulating activities are best handled in very small groups, where an interchange of pupils’ ideas is essential and pairing children for this learning scene is most likely to ensure that both children are involved,” explains Kutnick. “Larger groups of four to six tend to be associated with cooperative learning activities.”

Baines adds that teachers should consider the extra cognitive load that the group size is putting on a student and compare that with the difficulty of the task.

“Where group size becomes important is in the way it impacts on the challenge of working together - which, in turn, affects the group’s capacity to do the substantive task,” he says. “Working in pairs is normally much easier than working in small groups, which is much easier than working in large groups.”

It would follow, then, that the larger the group, the less demanding the task should be.

“If the...task is very challenging, then getting children to work in a smaller grouping can help them to focus their attention and do [it]. If a larger group is used with a cognitively challenging task, then this can overwhelm children - unless they are very experienced at working together,” says Baines.

That last point is an important caveat: if children are well trained in group work and know their group well, the task difficulty can be higher than for a group less trained and less used to working together.

Unfortunately, though, Kutnick says that it is still “very rare” for pupils to receive any training to work effectively and inclusively with groups in their classrooms. “Teachers are often too concerned to complete national curriculum tasks to think about the social pedagogic contexts within which pupils are asked to work,” he says, and even with the potential for training for effective group work, “teachers rarely commit themselves to provide the training and support of children’s groups”.

According to the book Promoting Effective Group Work in the Primary Classroom, co-written by Baines, Kutnick and Peter Blatchford, professor in psychology and education at the UCL Institute of Education, teachers should begin developing children’s group work skills and their formal group work experiences in pairs, and then build them up to groups of four or maybe five.

The reason why this slow build-up may not usually be followed is because of another critical component of group size: teacher workload. According to research by Baines, Blatchford and Kutnick, for example, teachers report that more smaller groups can increase the demands on them in terms of how they offer support - and how much planning and marking they have to do.

Baines was not being hyperbolic when he said the group size issue was complex, then. Clearly, there is a lot more to how many people you allocate to a group than you may have thought. And that might make those who already hate group work decide that it definitely is not worth doing. However, Baines stresses that this is the last thing they should do.

“There is much that needs to be considered, but, as we have seen with the schools and teachers we have worked with, once teaching staff have a handle on the main principles and practices that work best, it can be very easy to get fantastic collaborative group work going in even some of the most challenging of classrooms.”

Chris Parr is a freelance journalist

This article originally appeared in the 3 July 2020 issue under the headline “Tes focus on…Best numbers for group work”