Selection of any kind, including setting, fails to raise standards and increases social inequality, Lindsay Paterson, professor of education at Moray House Institute told the conference.
He was speaking on pupil achievement and educational change in anticipation of a Government consultation document on teaching strategies in S1-S2 to be published later this month.
Professor Paterson warned of further "social polarisation" if mixed-ability teaching was abandoned. Research had shown that the placing request legislation, through which parents exercise choice of school, had accelerated the social divide. The most socially advantaged used the mechanism most.
Scotland had been relatively successful in expanding educational opportunities and raising standards, he said, even if there was no evidence of improved performance in areas of deprivation. Pupils and parents, according to various surveys, had indicated broad support for schools and teachers.
Professor Paterson attributed the success in narrowing social inequalities, boosting exam passes, improved staying on rates and entry to higher education to comprehensive education. "There is nothing like the crisis of confidence in England," he said.
Further progress may be made by initiatives like supported study and early intervention programmes in nursery and primary, he said.