For most of us, the slow demise of the grammar school has offered little cause for lament. Divisive and ineffective, they have lurched on in a reduced, zombie like state, but have rarely threatened serious debate on the future of education. For a reactionary few, however, the resurrection of the grammar school has become somewhat of a raison d’être. No doubt these people will be delighted by today’s news.

Today the government has approved opening the first selective state school in England in 50 years. This is being achieved by the technicality of an extension of an existing grammar school, but in practice this will be the equivalent of a new grammar school opening. This is a mistake. Grammar schools are bad for inequality, bad for social mobility and have very little to recommend them at all.

Grammar schools are framed by a meritocratic ideal that they help smart kids achieve better results by focusing their education at a higher level. Their defenders say that they help improve the chances of bright kids from poorer backgrounds. The reality is quite different. Grammar schools take far fewer poorer students than other schools; they don’t improve the chances of working class kids going to a good university; and once you account for the educational background of their parents, and the children’s previous ability, kids from grammar schools aren’t any more likely to get any degree or a degree from an elite institution.

The evidence is clear: the only thing that grammar schools are any good at is increasing inequality. People who grew up in areas with selective schooling have more unequal incomes as adults. When you compare current counties with selective education to the rest of the country you can see that in selective counties most children have lower scores than the rest of the country and only the richest 10% see a small increase. Meanwhile children from the poorest 10% do far worse in these selective counties.

The reason why grammar schools don’t work and are bad for social mobility is obvious if you take more than a cursory glance at the issue. There is a straightforward relationship between parental income and cognitive development. Those with lower parental income score lower for cognitive development at an age 3 and the gap increases by age 5. And these scores are a good predictor for earnings in later life. Grammar schools effectively concentrate on helping children who are already doing well. This does nothing to tackle the educational inequality and extreme economic inequality that exists in this country.

There are educational interventions which can narrow the gap and have succeeded in doing so. Similarly, there is evidence that reducing economic inequality may improve education for everyone and reduce educational inequalities. The government should focus on these promising areas of research. Creating more grammar schools is a red herring that will only make the problem worse.

Tim Stacey, Senior Policy and Research Advisor