In part this is almost a tautology: children from poorer backgrounds tend to bring behavioural or motivational problems with them that make teaching harder. And in larger part it is a reflection of the effect of good schools on house prices: if a school becomes known for its quality and maintains it then after a while only wealthy families will be able to afford to live in its catchment area.
The pupil premium was first suggested by Professor Julian Le Grand in the 1980s as a way of tackling this problem. And that was certainly how it was seen by both the Conservatives and the Liberal Democrats before the Coalition came to power.
Here, for instance, is a Guardian article from 2008 that discusses a report on the subject from Le Grand and the Conservative think-tank Policy Exchange:
The report suggests that a pupil premium might stop schools trying to covertly select more able students by providing an incentive to admit pupils from the toughest backgrounds.
"A pupil premium would see extra money attached to students from deprived backgrounds," it says. "Schools that take large numbers of such students would be better off, giving them some additional resources to educate harder to teach children."
"If these resources were used successfully middle-class families would start to be attracted to the school, and schools in wealthier areas might broaden their admissions criteria to attract higher value pupils."That was certainly my understanding of the Pupil Premium when I blogged about it the following year. And it led me to suggest that the greatest problem with the policy would be selling it to the middle-class parents who were paying for it while seeing their own children squeezed out of the better schools.
That understanding also meant, incidentally, that the Lib Dems would have to lose their hang ups about parental choice and to embrace Michael Gove's free schools - or at least some other way of bringing new suppliers into the maintained education sector.
Three years on, we have a Conservative—Liberal Democrat coalition government and the Pupil Premium is being implemented, but the understanding of it, at least in Lib Dem circles, seems rather different.
Here is a BBC report on Nick Clegg's speech to last year's Liberal Democrat Conference:
Secondary schools will be asked to volunteer to hold the summer schools, which could offer a fortnight of catch-up lessons in basic skills such as literacy for 100,000 pupils.
The schools could also offer sports-based holiday projects for these 11-year-olds who have just left primary school.
The £50m will allow the scheme to be run for one year - with the funding drawn from the pupil premium budget, which will help schools to provide extra support for disadvantaged pupils.There is nothing here about choice or getting poorer children better schools. The Pupil Premium seems to have dwindled into a scheme that positions the poor child as a social problem who needs more money spent on him.
But if that child is in a bad school then it is hard to believe that another two weeks in the classroom or a bit more money for that school is going to make much difference. Perhaps it is the good schools that will run the summer schools, but the original idea of the Pupil Premium was to get poor children into good schools for their whole education, not just a fortnight.
And Nick Clegg seemed to grasp that this diminished Pupil Premium might not be so popular with the children to whom it is going to be applied in his admirable interview with children under the BBC School Report scheme. Having announced that money would be spent on summer schools, he realised that those interviewing him might not be too enthusiastic about attending them.
I am sure that summer schools could be good for children. And as Baden-Powell showed, if you get things right, children will come running.
But, as the it stands at the moment, the Pupil Premium seems to promise a world in which middle-class children in good schools go on holiday while working-class children in bad schools go to summer school.
As a Liberal (and as a former poor child) that is not a world I find particularly attractive.