If my children were in public school, they would spend their days in rooms with children all within a year of their own age, all from the same neighborhood and social stratum.

FORBES: Leadership Takes Many Forms - Like A 13-Year-Old Lecturer In A Ski Cap

Society being composed of social strata a family will find its children in competition with children from families in roughly the same social-economic stratum, with roughly the same total amount of family income to invest in children.

FORBES: Demographic Decline and Investment Intensity in Children -- Observations on China and Japan