Over the past three days we have been looking at the performance of academy schools in our region. MARTIN GEORGE pulls together the findings.

Why does it matter?

Academies spark real passion. To their most vehement opponents, they weaken local democratic oversight of schools and have heralded the marketisation of schools. To their most passionate advocates, they free schools from bureaucrats and give families real choice.

But whether you are positive, negative or indifferent on the issue, academies are a matter of fact, and how they perform really matters.

They educate about 43,000 children in Norfolk alone; they are responsible for millions of pounds of taxpayers' money, and if they do not succeed, education in our region will not improve as it needs to.

Another reason they matter is that academies are not only here to stay, their number is set to expand.

The Conservatives signalled in their election manifesto that they would increase the number of academies, and Education and Adoption Bill currently passing through Parliament will do just that.

It will introduce a new category of 'coasting schools', and non-academies that fall into it will have to convert if they cannot convince civil servants they have a clear plan to improve.

And all schools that Ofsted judges 'inadequate' will have to become academies, making what is currently at expectation of the Department for Education into a legal requirement.

How they're performing

Over the past three days, we have looked at four measures of how academies are doing - headline GCSE results and Ofsted grades, which are the government's main measures for holding schools to account, and whether they improve the life chances of disadvantaged pupils, a group they were first set up to help, and attendance, which is often lowest in deprived communities.

What have we found

As we said at the outset, any conclusions are tentative at best. MPs and academics who have analysed academies across England have said their conclusions have been limited by the short time that most have been in operation. In Norfolk and Suffolk, this is certainly true.

For GCSE results, sponsored academies - generally struggling schools starting from a low base - have seen their average rise, but their average still remains below the county's.

Critics of academies would say their low starting point gives them more scope to improve than other schools; supporters would point to the fact they did in fact improve.

But hidden behind the averages are big variations between academies. Some saw an initial improvement, followed by a decline. Some had generally sustained improvement. Some saw their results yo-yo.

Converter academies - generally high-performing schools - remained above the Norfolk average, but as more schools converted, their average took a downward turn.

For the first group of schools to convert, their already impressive results improved further.

For some later converters, results have dipped, and Ofsted's regional director raised concerns about the performance of isolated converter academies.

As far as Ofsted results go, it is a similar picture. Sponsored academies, which had the most room for improvement, did indeed improve. Converter academies, which had the furthest to potentially fall, saw more fall than rise, but most retained their previous grade.

As for disadvantaged pupils, in some years academies saw the gap between them and their peers narrow, and some saw it widen.

And as far as the school absence rate is concerned, it has consistently fallen in all types of schools, but slightly faster among sponsored academies.

The overall picture

Gordon Boyd, from Norfolk County Council, said it was a 'mixed picture' for academies and non-academies, and he is right.

Some academies have performed very well. Some have not. And some have varied from year to year. The same is true of non-academies.

And if there is any conclusion to be drawn from that, it is that becoming an academy is not, in and of itself, an automatic guarantee of sustained school improvement.