One of the best documented relationships in economics is the link between education and income: higher educated people have higher incomes. Advocates argue that education provides skills, or human capital, that raises an individual's productivity. Critics argue that the documented relationship...

Economists attempting to explain the widening of the black-white wage gap in the late 1970's by differences in school quality have been faced with the problem that recent data reveal virtually no gap in the quality of schools attended by blacks and whites using a variety of measures. In this...