It is repeatedly argued by politicians (as well as by quangos like the Social Mobility Commission and think-tanks like the Sutton Trust) that Britain’s top universities unfairly favour applicants from independent, fee-paying schools.
The evidence cited for this claim is that only seven per cent of British children attend private schools, but they account for 23 per cent of young people entering Russell Group universities, and for 42 per cent of those going to Oxbridge.
In a speech in Derby in 2018, the then prime minister Theresa May said: “Almost a quarter of the students at our research-intensive universities come from the seven per cent of the population who go to private school.”
She concluded from this: “For the boy from a working-class home here in Derby, the odds are stacked against him.”z
But it doesn’t necessarily follow that if only seven per cent of children attend private schools, they should account for only seven per cent of students at top universities.
Bruce Charlton, former visiting professor of theoretical medicine at the University of Buckingham, has pointed out that 18 per cent of A-level students are in private schools, and this is the pool from which universities are selecting.
We should therefore expect youngsters educated in the private sector to account for at least 18 per cent of entrants to the top universities, not seven per cent.
Moreover, children at private schools out-perform children at state schools when it comes to achieving the qualifications necessary to get into a good university.
They may only account for 18 per cent of those sitting A-levels, but between them, independent school pupils make up 32 per cent of all A-level candidates who achieve three A grades or better (the sorts of grades normally required to get an offer from Oxford or Cambridge).
Almost half (48 per cent) of all the A-levels achieved by independent school pupils in 2017 were at grade A or A*, compared with “only” 26 per cent nationally.
It is because they get better A-level results that more privately-educated students get into our top universities. But what explains this?
Charlton points out that private schools often select their intake (at least to some extent) by ability, whereas the vast majority of state schools do not.
It follows that the average ability level in the independent schools must be higher, which means we should expect their alumni to perform better at A-level, and therefore to be over-represented in the best universities (assuming the best universities are selecting on meritocratic criteria).
When it comes to educational attainment, cognitive ability is crucial. It has far more effect than social class background or the type of school children attend.
Reviewing evidence from Britain’s National Child Development Study (a 1958 birth cohort), Dr. Gary Marks, a sociologist at the University of Melbourne, finds that social class background had no significant effect on university entry once a child’s GCSE and A-level scores were taken into account, and that school exam success largely reflected their cognitive ability as measured by IQ tests at age 11.
Marks reports that IQ and GCSE performance correlated very highly (r = 0.7). Controlling for family income and class background, the probability of a student in the top fifth of IQ scores achieving A-levels or higher was 70 percentage points greater than that of a student in the bottom fifth.
When it comes to passing exams, therefore, ability trumps class. The main reason pupils from private schools out-perform those from non-selective state schools in university entry is that they are, on average, brighter.
Robert Plomin’s research confirms this. He is Research Professor in behavioural genetics at King’s College London, where he has studied 16,000 pairs of twins to find how strongly the genes we inherit from our parents correlate with measurable features of our personality and behaviour.
There is rarely only one gene for any one trait: hundreds or thousands of genes commonly interact to produce many different variations. By aggregating these tiny individual effects, Plomin identifies ‘polygenic scores’ which correlate significantly with various different traits.
One of the traits he looks at is academic attainment, measured by years of education (he finds an even stronger association with IQ scores, but the sample sizes are very small because few children nowadays are IQ-tested).
He reports that children in private schools have “substantially higher educational attainment polygenic scores” than those in state comprehensives. The DNA they inherit from their parents is wired for academic success.
Ability differences don’t explain everything. There is also evidence that private schools on average develop the potential of their students more successfully than the state sector does.
My research with Rod Bond, a psychology lecturer at the University of Sussex, on the 1958 birth cohort found that those attending private school at 16 gained better qualifications than those attending state schools, independently of their ability.
This effect was modest but significant, and it operated mainly by raising the level of motivation of students in the independent sector.
In 2016-17, 25 per cent of pupils gaining 3 A grades or better at A-level were in private schools, but only 23 per cent of young people entering Russell Group universities that year were from private schools. Judging by these figures, applicants from private schools appear to be slightly under-represented in the “research-intensive universities” which Mrs May was so concerned about.
This under-representation is likely to increase, the more the government pressurises our top universities into taking fewer students from the independent sector.
Little wonder some private school heads have recently begun to complain about unfair treatment by universities of applications from their pupils.
(This article is based on material from Peter Saunders, Social Mobility Truths, published by Civitas in 2019)
Peter Saunders is Professor Emeritus of Sociology at the University of Sussex, Distinguished Fellow of the Centre for Independent Studies in Sydney, and a Professorial Fellow at Civitas in London. He has spent many years researching social mobility in Britain and is author of Social Mobility Truths, published by Civitas in 2017. More details can be found on his website: petersaunders.org.uk.
 See, for example, Social Mobility Commission, State of the Nation 2018-19, op cit., p.53; Sutton Trust, cited by Sean Coughlin, ‘Oxbridge over-recruits from eight schools’ BBC News 7 December 2018, https://www.bbc.co.uk/news/education-46470838; Damien Hinds speech to Resolution Foundation, 31 July 2018 www.gov.uk/government/speeches/education-secretary-sets-vision-for-boosting-social-mobility
 Theresa May, The right education for everyone Speech delivered in Derby, 19 February 2018 www.gov.uk/government/speeches/pm-the-right-education-for-everyone
 Bruce Charlton, Proportion of private school kids applying to college is about 18%, not 7% 14 July 2010 https://charltonteaching.blogspot.com/20/10/17/proportion-of-private-school-kids.html
 Social Mobility Commission, Elitist Britain? 2014, p.16. The University of Oxford notes that 28.4% of independent school candidates get AAA+ grades compared with 6.6% of state school candidates – Access and Participation Plan 2019-20, p.5
 Bruce Charlton, ‘Social class and IQ’ Mensa magazine, December 2008. The reason we would expect an even higher proportion of private school students to make it into Oxbridge than into the Russell Group universities has to do with the properties of the normal distribution curve. If the average IQ in private schools is higher than in state schools, then the number of students at the very highest end of the IQ distribution (say, 2 or more standard deviations above the mean) will be much higher – and it is from this extreme end of the distribution that the very top universities will recruit.
 Gary Marks, Education, social background and cognitive ability, Routledge, 2015
 Robert Plomin, Blueprint: How DNA makes us who we are, Allen Lane, 2018, pp.172-3
 Rod Bond and Peter Saunders ‘Routes of success’ British Journal of Sociology, vol.50, 1999, p.239. Interestingly, Plomin suggests that private schools add little to the potential that their students already have, arguing that they select on the basis of cognitive tests which fully predict their later achievements in GCSE examinations. Against this, even critics accept that independent schools get more from their pupils due to their ‘respect [for] the need for a disciplined environment for learning’ and the attention they give to ‘generating a positive and therefore motivating experience’ (Francis Green and David Kynaston, ‘Britain’s private school problem’ The Guardian 13 January 2019)
 Damian Hinds speech to Resolution Foundation, 31 July 2018, op cit
 Nicola Woodcock, ‘Private woe over rise of state pupils at Oxbridge’ The Times, 11 May 2019