Addressing the Association of Directors of Education in Scotland at its annual conference in Grangemouth, Graham Donaldson said Scotland was doing well in international league tables but could do far more for many of the disadvantaged - the principal theme of ministers in their drive on inclusion and equality.
Despite the great increase in numbers entering university little if any progress had been made in increasing the proportion from disadvantaged backgrounds. "We also know that the proportion of 16-19s who are not in education, training or employment was still around 14 per cent in 2001, the same figure that was recorded in 1992. This must reflect a huge waste of talent," Mr Donaldson said.
International comparisons ranked Scotland eighth in mathematics, seventh in reading and fourth in science but results were much less encouraging when a comparison was made of the gap in performance between the highest and lowest socio-economic groups.
Countries such as Canada, Finland, Japan, Korea and Sweden had above average performance but the impact of disadvantage was below average.
Mr Donaldson said that looked-after children were "still falling through the cracks in the system" and leaving school with few qualifications. The most conspicuously disadvantaged were doubly disadvantaged by educational failure.
"We have also seen examples of some very inadequate provision being made for pupils who have been excluded or who have become otherwise disaffected from the mainstream system. Where they have attended some form of provision, they too often experience an impoverished curriculum, severely reduced hours of attendance and ineffective learning and teaching.
"These are among the most challenging pupils for us all but the consequences of failure to address this challenge are very significant for society and disastrous for the young people themselves."
Mr Donaldson accepted, however, that inclusion was not well served by "unrealistic expectations of what can be achieved". It was a challenge to match the rhetoric of inclusion to those who are disruptive, alienated or have complex special needs. "Good teachers who are struggling to cope must be supported," he said.
But picking up a familiar HMI refrain, Mr Donaldson stressed high expectations, high achievement and real success as essential components of effective inclusion.