School competition works in exactly the same manner as other forms of competition that is. It's something that happens at the margin, that margin then dragging up the performance of others:

There is no evidence that academies perform better than council-maintained schools. The white paper highlights impressive improvements in primary schools – 85% of those are still maintained. 82% of maintained schools have been rated good or excellent by Ofsted, while three times as many councils perform above the national average in terms of progress made by students than the largest academy chains. Where a school is failing, there is no question that action must be taken – but converting every school to an academy will not tackle those issues.

Think of a different arena to study the effects of competition. We know very well that the firms who export are those at the productivity boundary: exporting firms are near always significantly more productive than the other domestic firms in that same sector. Now think of the flip side of that statement: imports from Germany into Britain expose British companies to the finest and most productive German forms. This is one of the major channels by which trade improves productivity. Domestic firms must compete against those imports and near by definition those imports are coming from firms with greater than average productivity. Thus the domestic firms have to pull their socks up.....or be replaced by those who do.

Imports are not, of course, a majority of the UK economy: but that exposure to the best does improve matters over the whole economy. Now back to academies and schools: that some small portion of the education system are academies is exactly what, entirely analagous to that effect from trade and imports, is improving the non-academy state sector. To state that non-academies are improving too is not some symptom of a failure of the program, it's evidence of the success of the program: competition works.

At which point, turning all schools into academies. If it works, as it does, if it's working, as it is, then why not? After all, we do all believe in evidence based policy making, don't we? Good, academies, the competition and freedom to experiment that they bring, are improving the school system by their existence. Thus let's do more of it so as to have an ever better education sector.

Unless, of course, we'd prefer to return to the policy based evidence making of yore which insisted that competition was a bad thing....