Professor Geoff Whitty, director of the Institute of Education at London University, last week told a conference in Aberdeen that practices in schools and other educational institutions were often part of the problem and reinforced inequalities.
Studies in Scotland and England had shown that "huge" differences remained in relative attainment between children from affluent areas and those in poorer communities, despite some progress in narrowing the gap. "The inroads are tiny," Professor Whitty said.
He added: "Schools make a difference - but let's be realistic about how far."
A third of households in Scotland, he stressed, are in or on the margins of poverty, one of the highest rates in the developed world. Multiple causes of disadvantage interacted with education to dampen achievement.
"The notion that education interventions alone can transform the life chances of large numbers of disadvantaged children is clearly not tenable, certainly in the short term, even although we can point to individual cases of bucking the trend," Professor Whitty said.
In recent years, attention had been on school improvement, which stressed that solutions lay with teachers. "The problem facing us is that it is much easier for some schools to improve than others," he said.
Studies showed that schools which had initially made progress in overcoming disadvantage began to slip back after five years. "Even if some schools succeed against the odds for a time, we must beware of basing a national strategy for change on the efforts of outstanding individuals working in these areas," Professor Whitty said.
Along with colleagues, he has studied the first phase of new community schools in Scotland which placed the emphasis on inter-agency working to address the needs of children in the round. Social justice was a term used north of the border but not south of it, he noted.
Carol Campbell, an Institute of Education lecturer and a Scot, said that experience of full-service schools in the United States over a 10-year period showed positive results overall. Scotland had adapted its practices.
More than 80 per cent of the outcomes in the US were positive, Dr Campbell said.
Despite some negative publicity about the impact on attainment, the Scottish study of new community schools was equally positive. It was never going to be possible to raise attainment in the first three years. But there were no detrimental effects in the 170 schools in the study carried out between 2000 and 2003.
"The schools that were involved in this programme were improving at a faster rate than schools nationally, including behaviour, standards of work, personal and social education, and management of support for pupils," Dr Campbell said.
Almost half the primaries and two-thirds of secondaries rated the impact of the initiative on pupil attitudes as "considerable". Health promotion projects, breakfast clubs and anti-bullying measures were features. More services were offered by different agencies.
The greatest effect, she said, was on pupils at risk of exclusion. Schools and others were better prepared to identify those who were vulnerable.
But professional barriers remained. There were was little time for different staff to meet and class teachers were often outside the initiative.
Professor Whitty concluded: "Integrated community schools are a creditable development."