It is rare that a politician refers to education without pledging to reduce “educational disadvantage”. Yet the same speeches will be made next year as well. The Organisation for Economic Co-operation and Development recently reported that the gap in average educational achievement between students from the lowest and highest socioeconomic groups in Australia remains at close to three years of schooling. Why is this? Not because of high class sizes: Australia’s are among the best in the world. And not because of lack of resources: even before the Rudd government’s bizarre “Building the Education Revolution” program began, Australia was high…