Private school versus state school: Are we exaggerating the value of independent education?

Michael Gove is a clever man, choosing to educate his daughter at a state secondary school. He gains political points for being the first Conservative Education Secretary to choose a state school for his child.

But, more significantly, he has not been duped – as many middle-class parents are – into believing it is worth paying an arm and a leg for a private education.

Heads of private schools in particular habitually trumpet the so-called "apartheid" between independent and state schools, pointing to how much their alumni dominate the green benches or the city trading floors.

Clever. For it both entices and scares parents, understandably desperate to secure the best possible future for their children. But, actually, the independent school premium is very likely to be greatly exaggerated. Parents: keep your hands in your pockets.

We can measure how well those educated in the independent sector do compared to those in the state sector by comparing educational attainment and salaries in adulthood.

Yes, it’s true, that on average those in the independent sector achieve higher results. They are more likely to get higher grades at GCSE, the A-levels needed to get into more selective universities, and a first or 2:1 at degree level.

When they leave university, after three and half years, they are more likely to be earning more money. Even in the long-term, as the 2009 Milburn Report on social mobility showed, they are disproportionately represented in the top professions.

Impressive, right? Well, we can’t be sure what causes this premium. Is it something these schools are doing, or is it in fact more about the type of students they attract?

Academics such as Professor James Heckman and Dr Leon Feinstein have shown that long-term educational performance is determined at a very early age, since the brain is most malleable in infancy and skill formation is complementary.

Private schools, especially as many are selective, may simply be recruiting students that have higher prior academic attainment and thus more potential in the long-term.

Since early cognitive ability is strongly associated with parental socio-economic background, expensive private schools – where average annual fees for day independent schools now stands at £12,153 – may also be benefiting from an intake that is disproportionately from more affluent homes.

Luckily, education policy geeks have devised a new way of assessing what institutions actually add to the performance of children who start school, intellectually, from different places. It is called the Value-Add (VA) score.

Parents should use this, rather than raw scores such as the number of passes at GCSE, because it demonstrates how much, on average, a school is likely to add to the academic attainment of children between Key Stage 2 (aged 11) and Key Stage 4 (GCSE) considering their variable ability when they first started.

Essentially, your child is more likely to get higher GCSE grades in a school that has a strong VA score with a relatively low GCSE pass rate compared to a school with a low VA score but an impressive GCSE pass rate.

Unfortunately, however, private schools do not publish their VA scores. Government should make them provide the necessary data and publish the results.

Parents may be surprised to discover that their child is just as likely, if not more likely, to get exceptional grades at good state schools – and there are many with impressive VA scores – than if they were at a private school.

Indeed, until 2010, independent schools did publish a slightly different score which measured the Contextual Value Add of institutions between GCSE and A-level; analysis of the results shows that a sizeable proportion of post-16 provision in the state sector is adding more value to a child’s educational progress than the independent sector.

Academics have shown that, even if you control for early academic ability and parental backgrounds, there is still a long-term salary premium from attending independent school.

In fact, they calculate that a child educated in the independent sector is likely to earn 20 per cent more in their early thirties than a child with similar early characteristics and background than a child in the state sector.

A note of caution on this data, however: even though there is a salary premium, how do we know the activities of the school are creating it?

Admittedly, many schools may be more likely to enhance children’s attainment since the teaching qualifications tend to be higher, and class sizes smaller, which is likely to be having some impact on career progression. And the emphasis and provision of extra-curricular activity is stronger, which may help with the fostering of softer skills such as confidence and motivation which is important in the modern labour market.

But, equally, the premium may also be partially caused by the networks these pupils have, derived from their parents who are much more likely to be in professional occupations and better connected with employers who can give their children life-enhancing information, experiences and opportunities.

Such pupils are also more likely to have cultural and financial capital, enabling them to have longer for, and be better at, seeking out the best job opportunities.

In other words, the resources and contacts children from affluent backgrounds have in adulthood could be more important than the school they attended in explaining why they succeed in the labour market.

So, considering the uncertainty around the extent and cause of the independent school premium, is it really worth paying for a private school education? Indeed, analysis has shown that the average cost of attending an independent school still far exceeds the premium you would need to pay to buy a house in a catchment area of one of the top secondary schools in the country.

Experiences and evidence shows a state education can be just as good, if not better. Even the Prime Minister and his wife have followed the Education Secretary, announcing this week they will send their daughter to a state school. Maybe it’s time for even more parents to follow in Gove’s footsteps.

Ryan Shorthouse is the Director of Bright Blue, the think tank for liberal conservatism