A high-quality education is critical to the future well-being of a child—and thus also to the nation as a whole. By one estimate, a high school dropout in the United States will earn nearly a quarter of a million dollars less over his lifetime than a high school graduate who completes no further education. He will also contribute $60,000 less in tax revenues. Aggregated over a cohort of eighteen-year-olds who never complete high school, these losses add up to $200 billion.1 Moreover, gaps in the educational achievement of children by race and social class are large and persistent. For example, among eighth graders in 1988, 95 percent from the most advantaged families had received a high school diploma within six years, compared with only 66 percent from the least advantaged families.2 According to the National Assessment of Educational Progress, 9 percent of black and 13 percent of Hispanic eighth graders perform at or above the proficient level in mathematics, compared with 39 percent of whites.