But all this just makes the positive effects in international tests more noteworthy — we can only speculate about what could be achieved if countries took system design seriously. And in terms of system design, English politicians have a lot to think about. Here, we only focus on a couple of the most salient points.

First, in order to have strong competition that targets quality deficiencies, schools must face the threat of potential pupil migration to other providers. In theory, this should have introduced by the 1988 Education Reform Act, which established the right of parents to apply to any school in England. But neither this piece of legislation nor subsequent education reforms have adequately addressed a key hurdle to expanding choice: the crucial role that proximity to residence still plays in pupil allocation. Indeed, most publicly-funded schools still use proximity as their main tiebreak device in the case of oversubscription.

Why is this a problem? Because when sought-after schools use proximity as their oversubscription admissions criterion, wealthier parents move closer to them in order to secure a place for their children. This also means that people who cannot afford to move are often left with whatever schools are not oversubscribed, diluting their right to choose schools to a theoretical concern. Indeed, a vast amount of research in England and abroad identifies a link between school quality and house prices, which decreases in importance (or is obliterated entirely) as proximity becomes less important for admissions. By reducing the link between residential location and school choice, the latter can be expanded among the large part of the population who cannot afford to move.

But what is the alternative to the proximity rule? All publicly-funded schools should utilise lotteries in the case of oversubscription. This is the tiebreak device used in the American charter school sector, and an approach that is becoming more popular among English academies and free schools. By using lotteries, the premium of living close to schools disappears, the choice set for the less wealthy is consequently increased, and de facto market areas expand significantly. It therefore also sharpens competitive incentives to raise achievement for all pupils, as popular schools will no longer be able to rest on the laurels of having an advantaged intake as the result of residential sorting.

Of course, in the long run the solution is to improve the supply-side dynamic in the schools market. If it is relatively easy to start new schools and expand existing good ones, the tiebreak device becomes much less important. But despite the free schools programme, this is clearly not the case in England. This is because the approval process for new schools still involves some bureaucracy, and since the government commits itself to finance upfront capital costs, it is also forced to reject applications from perfectly good providers simply because it would cost too much to approve them.