School improvement, like motherhood, has many advocates. Everyone is for it, without having to campaign actively on its behalf. And just as the 100% of people who have had mothers think they know how mothering could be done better, so the (nearly) 100% of people who have been pupils in schools, or have even taught in or managed them, think they know how schools can be im- proved. More precisely, they are sure that schools ought to be improved. The...