It is a pity we are still being subjected to an unnecessary row about the 25 schools which wish to teach in English but have been refused permission to do so.
If the struggle is going to continue, then people need to be a bit more careful with their words than they have been lately. It has become customary to write as if it was an established fact that mother-tongue education was more effective, and this was being resisted only by Luddites who would not accept the scientific evidence.
This is not actually true.
What is true is that, as the Education Department used to say in a rather carefully-chosen phrase, most of the studies internationally have concluded that - other things being equal - education in the mother tongue of the student will be more successful.
If you look at the evidence more closely, though, there is still plenty of room for scepticism.
There is a danger in all science, and particularly in the so-called social sciences, that the researcher will come to a conclusion which fits his existing expectations and preferences. So when a topic attracts a large number of studies, it is a good idea to look at why it is 'hot' and what the researchers may be looking for.