In 2011, two thirds of primary academies were standalone – but by 2015 65 per cent were in a multi-academy trust. For many schools, outcomes have improved because they support each other

The government’s academy programme is growing fast. Sixty five per cent of secondary schools and 18 per cent of primaries now operate outside of local authority control, with their numbers set to swell rapidly over the next few months.

Increasingly, however, those schools aren’t operating as standalone institutions, but are finding new and effective ways of working together. Back in 2011, two thirds of primary academies were standalone, with only a third being part of a group. By the end of 2015, the picture had flipped, with 65 per cent of primary academies now forming part of a multi-academy trust (MAT). The greater size and capacity of most secondary schools means that the picture here is less pronounced, but the trend is heading in the same direction, with close to half of secondary academies now part of MATs.

So what do we know about the effects of these changes on England’s schools? It’s fair to say that the jury is still out on the effects of academisation per se. Last year’s education select committee report into academies and free schools put it baldly: “Current evidence does not allow us to draw conclusions on whether academies in themselves are a positive force for change.”

It is shared accountability that makes a difference, rather than the type of school

The same report was at pains to point out that “academisation is not always successful nor is it the only proven alternative for a struggling school. Both academies and state-maintained schools have a role to play in system-wide improvement.”

So far, so mixed. Where things get more interesting, though, is if we look at the emerging evidence about partnerships.

Another education select committee report, this time focused on school partnership and co-operation, found significant evidence for the benefits of formal collaborations between schools, describing them as “an increasingly important part of a self-improving or school-led system”. Eighty seven per cent of headteachers and 83 per cent of chairs of governors interviewed by the authors described partnership with other schools as “critical to improving outcomes for students”.

Interestingly, the benefits of collaboration aren’t confined to multi-academy trusts. A report by the National College for School Leadership into “hard” federations (groups of maintained schools with shared governance) found that schools in federations performed better than schools with apparently similar characteristics that had not federated.

However, not all partnerships are as effective as others, according to studies by the Sutton Trust. Its investigations into the impact of academy chains on low income students, Chain Effects and Chain Effects 2015, found “very significant variation in outcomes … both between and within chains”. It identified five chains that are promoting high attainment for disadvantaged pupils.

However it also found that some chains were highly ineffective, and were failing to improve the prospects of their disadvantaged pupils. The reasons for these differences weren’t always clear, but the authors note that the groups with the best outcomes for disadvantaged pupils had two things in common: they had been running schools for a number of years, and had expanded slowly.

So what does all this tell us? It’s still early to attempt to draw any lasting conclusions on the effects of the significant structural changes taking place in English schools. The evidence so far, though, suggests that, done right, formal partnerships can help schools to effectively navigate these choppy waters.

It is shared accountability that is most likely to make a difference, rather than any advantage or disadvantage in school types. The reason is simple but profound. As the head of a school that had recently joined a Mat put it: “We are accountable for each other, and therefore it is imperative we support each other to improve.”

ASCL, together with the National Governors’ Association and the education law firm Browne Jacobson, has produced guidance, Forming or Joining a Group of Schools: staying in control of your school’s destiny, to help school leaders and governors to explore the potential of formal collaboration between schools.