
Implicit in these very different proposals is the assumption that urban schools are failing because they are run badly, and that the solution lies in improving their management. Over the last five years, we have been involved in a wide-ranging research project that provides compelling evidence to the contrary. Our findings show that the root of the problems facing urban schools can be found in gradual but extremely powerful changes in the nation's economy — not the least of which is the increasingly unequal distribution of family incomes. Policies that address the consequences of these changes, which recent poverty figures show have worsened, are more likely to improve the life chances of the children from low-income families.
For the first three-quarters of the 20th century, economic growth, fueled in large part by the increasing educational attainments of successive generations of Americans, was a rising tide that lifted the boats of the rich and poor alike. During the most recent three decades, by contrast, the fruits of economic growth have not been widely shared and the gap between the incomes of the nation's rich and poor families has grown enormously.
Little noticed, but vital for our nation's future prosperity, is the equally dramatic widening of the gap between the educational attainments of children growing up in rich and poor families. Between 1978 and 2008, the gap between the average mathematics and reading test scores of children from high- and low-income families grew by a third. This growing test score gap has been reflected in a growing gap in completed schooling. Over the last 20 years, the rate of affluent children who completed college increased by 21 percentage points, while the graduation rate of children from low-income families increased by only 4 percentage points.
Growing economic inequality contributes in a multitude of ways to a widening gulf between the educational outcomes of rich and poor children. In the early 1970s, the gap between what parents in the top and bottom quintiles spent on enrichment activities such as music lessons, travel and summer camps was approximately $2,700 per year (in 2008 dollars). By 2005-2006, the difference had increased to $7,500. Between birth and age 6, children from high-income families spend an average of 1,300 more hours than children from low-income families in "novel" places — other than at home or school, or in the care of another parent or a day care facility. This matters, because when children are asked to read science and social studies texts in the upper elementary school grades, background knowledge is critical to comprehension and academic success.
Historically, we have relied on our public schools to level the playing field for children born into different circumstances, but in recent years, the gaps in achievement and behavior between high- and low-income children have only grown wider. Why? For one thing, residential segregation by income has meant that poor children are concentrated in the same schools to a much greater extent today than 40 years ago. As a result, children from low-income families are far more likely to have classmates with low achievement and behavior problems, which have a negative effect on their own learning. Children from poor families are also especially likely to attend schools with high rates of student turnover during the school year, and there is clear evidence that students learn less under such circumstances. In Chicago's public schools, 10 percent of students change school every year and it is not uncommon for some classrooms to have five new students arrive during the year. Research shows that students learn less if they attend schools with high student turnover during the school year.