A warning to education reformers emerges today (Friday) in a research study from two leading Scottish academics.
In an analysis of social mobility in 20th century Scotland, Lindsay Paterson and Cristina Iannelli of Edinburgh University suggest that reforms which aim to improve people's prospects may be based on a false premise.
The study, funded by the Economic and Social Research Council, says it is the jobs people do, and how employment is structured, that make the difference, not education. The authors conclude that there has been a "lack of any impact on social mobility from Scotland's fairly thorough introduction of comprehensive secondary schooling in the 1970s".
Professor Paterson said these latest findings did not contradict earlier research which showed that comprehensive schooling had reduced social inequalities in attainment. "That still holds true," he said, "it's just that this has not been powerful enough to make an impact on social mobility and the class structure."
The report states: "If education could have an independent effect, then Scotland should show it; but it does not. The similarity of social mobility experience to England and Wales shows that wider social and economic reforms are more important."
Professor Paterson and Dr Iannelli point to the examples of Sweden, France and the Netherlands, where economic policies have led to the growth of "social fluidity".
Basing their conclusions on annual household surveys north and south of the border and on a 1974 study of mobility in Scotland (involving around 31,000 people), they found that mobility was linked to social class and to whether people left school at the earliest opportunity.
But the links weakened the higher the level of education went. "This means that, once a person reaches an upper secondary or tertiary qualification, the effect of social class of origin is less important in determining their later social class than for a person who has only compulsory education or less," the researchers state.
"The same result can be interpreted in a different way: if middle class children do not reach the highest educational qualifications, they have other family resources, for example financial support or social networks, that enable them to maintain their social class of origin."
Professor Paterson and Dr Iannelli go on to caution that some policies such as top-up tuition fees may make matters worse.
Since a higher proportion of parents now come from the middle classes, they will try to prevent their children falling down the social ladder and may put pressure on politicians to differentiate between the status of particular universities, perhaps by charging higher fees.
The report comments: "The best labour market rewards might then go to graduates from the highest-status universities populated by the most middle class students. In such circumstances, social fluidity would at best remain unchanged and could start to worsen for the first time in at least half a century."
The study concedes, however, that there may be a more optimistic conclusion. Under this scenario, further educational expansion could squeeze out inequality if it went hand in hand with insisting that recruitment into jobs was based on merit.