It is well known that the income divide in the United States has increased substantially over the last few decades, a trend that is particularly true for families with children. In fact, according to Census Bureau data, more than one-third of children today are raised in families with lower incomes than comparable children thirty-five years ago. This sustained erosion of income among such a broad group of children is without precedent in recent American history. Over the same period, children living in the highest 5 percent of the family-income distribution have seen their families’ incomes double.

What is less well known, however, is that mounting evidence hints that the forces behind these divergent experiences are threatening the upward mobility of the youngest Americans, and that inequality of income for one generation may mean inequality of opportunity for the next. It is too early to say for certain whether the rise in income inequality over the past few decades has caused a fall in social mobility of the poor and those in the middle class—the first generation of Americans to grow up under this inequality is, on average, in high school—but the early signs are troubling.

Investments in education and skills, which are factors that increasingly determine outcomes in the job market, are becoming more stratified by family income. As income inequality has increased, wealthier parents are able to invest more in their children’s education and enrichment, increasing the already sizable difference in investment from those at the other end of the earnings distribution. This disparity has real and measurable consequences for the current generation of American children. Although cognitive tests of ability show little difference between children of high- and low-income parents in the first years of their lives, large and persistent differences start emerging before kindergarten. Among older children, evidence suggests that the gap between high- and low-income primary and secondary-school students has increased by almost 40 percent over the past thirty years.

These differences persist and widen into young adulthood and beyond. Just as the gap in K–12 test scores between high and low-income students is growing, the difference in college graduation rates between the rich and the poor is also growing. Although the college graduation rate among the poorest households increased by about 4 percentage points between those born in the early 1960s and those born in the early 1980s, over this same period, the graduation rate increased by almost 20 percentage points for the wealthiest households.

Given how important education and, in particular, a college degree are in the labor market, these trends give rise to concerns that last generation’s inequities will be perpetuated into the next generation and opportunities for upward social mobility will be diminished. The emphasis that American society places on upward mobility makes this alarming in and of itself. In addition, low levels of social mobility may ultimately shift public support toward policies to address such inequities, instead of toward policies intended to promote economic growth.

While the urgency of finding solutions to this challenge requires rethinking a broad range of social and economic policies, we believe that any successful approach will necessitate increasing the skills and human capital of Americans. Decades of research demonstrate that policies that improve the quality of and expand access to early-childhood, K–12, and higher education can be effective at ameliorating these stark differences in economic opportunities across households.

Indeed, making it easier and more affordable for low-income students to attend college has long been a vehicle for upward mobility. Over the past fifty years, policies that have increased access to higher education, from the GI Bill to student aid, have not only helped lift thousands of Americans into the middle class and beyond, but also have boosted the productivity, innovation, and resources of the American economy.

Fortunately, researchers are making rapid progress in identifying new approaches that complement or improve on long-standing federal aid programs to boost college attendance and completion among lower-income students. These new interventions, which include high school and college mentoring, targeted informational interventions, and behavioral approaches to nudge students into better outcomes, could form the basis of important new policies that aim to steer more students toward college.

A founding principle of The Hamilton Project’s economic strategy is that long-term prosperity is best achieved by fostering economic growth and broad participation in that growth. This principle is particularly relevant in the context of social mobility, wherein broad participation in growth can contribute to further growth by providing families with the ability to invest in their children and communities, optimism that their hard work and efforts will lead to success for them and their children, and openness to innovation and change that lead to new sources of economic growth.

In this spirit, we offer our “Thirteen Economic Facts about Social Mobility and the Role of Education.” In chapter 1, we examine the very different changes in income between American families at opposite ends of the income distribution over the last thirty-five years and the seemingly dominant role that a child’s family income plays in determining his or her future economic outcomes. In chapter 2, we provide evidence on the growing divide in the United States in educational opportunities and outcomes based on family income. In chapter 3, we explore the great potential of education to increase upward mobility for all Americans, with a special focus on what we know about how to increase college attendance and completion for low-income students.