The results indicate that heterogeneity of race and heterogeneity of family educational background can increase the achievement of children from weak educational backgrounds with no adverse effect on children from strong educational backgrounds.

In a high school, the norms act to hold down the achievements of those who are above average, so that the school's demands will be at a level easily maintained by the majority.

The higher the social class of other students the higher any given student's achievement.

Children from a given family background, when put in schools of different social compositions, will achieve at quite different levels.

It is one thing to take as a given that approximately 70 percent of an entering high school freshman class will not attend college, but to assign a particular child to a curriculum designed for that 70 percent closes off for that child the opportunity to attend college.

Grades are almost completely relative, in effect ranking students relative to others in their class. Thus extra achievement by one student not only raises his position, but in effect lowers the position of others.

The results indicate that heterogeneity of race and heterogeneity of family educational background can increase the achievement of children from weak educational backgrounds with no adverse effect on children from strong educational backgrounds.