Students from high-income families are considerably more likely than students from low-income families to earn a college degree. As reported in "Indicators of Higher Education Equity in the United States: 45 Year Trend Report," a February 2015 report by the Pell Institute and the Alliance for Higher Education and Democracy (AHEAD), dependent students from families in the highest income quartile are now eight times more likely than dependent students from families in the lowest income quartile to earn a bachelor's degree by age 24. Since 1970, the share of dependent students from high-income families earning a bachelor's degree has nearly doubled (rising from 40 percent to 77 percent), while the share of dependent students from low-income families earning a bachelor’s degree has remained virtually unchanged (moving from just 6 percent to 9 percent).

These statistics, along with other indicators in the report, illustrate the magnitude of progress that our nation must make if it is to achieve equity in higher-education outcomes. Existing public policies and institutional practices are clearly insufficient. Not everyone needs a college degree, but far too few people in the U.S. — and especially far too few people from low-income families and other groups that are historically underrepresented in college — are getting one.

To improve equity in higher education degree attainment — and the many benefits that come with higher education — we need public policies and institutional practices that effectively level the playing field. We need to ensure that all high school graduates are academically ready for college-level work, and that students and their families can afford the costs of attending college without excessive reliance on loans. As documented in the "Indicators" report, the percent of costs paid by state and local funds has been declining in recent years, while the percent paid by students and their families has been increasing. State and local sources accounted for only 39 percent of higher-education institutions' revenue in 2012, down from 57 percent in 1977. At the same time, students and their families accounted for 49 percent of revenues in 2012, up from about 33 percent in 1977. Because increases in the Federal Pell Grant have failed to keep pace with the growth in college costs, the maximum Pell Grant covered only 27 percent of costs in 2012, down from 67 percent in 1975.

Given these trends, it is not surprising that students and their families are increasingly relying on loans to pay college costs. Both the percent of students who borrow to pay college costs and the amount they borrow have risen considerably since the 1990s. For instance, about 71 percent of 2011-12 bachelor's degree recipients borrowed, up from 49 percent in 1992-93. Over the past two decades, the average amount borrowed nearly doubled (in constant 2012 dollars) among students graduating with a bachelor's degree, rising from $16,500 in 1992-93 to $29,400 by 2011-12. Clearly, students must now be willing to take on the risk of student loan debt if they want to pursue higher education. But loan debt is risky — especially for students who attend institutions with low completion rates and for students with characteristics that put them at risk for not completing their degree programs.

Closing the considerable gaps in higher education attainment will not be simple or easy. Improving equity in attainment is a complex, multifaceted challenge that cannot be "solved" by changing just one policy or practice. As Joni Finney and I argue in our recent book, The Attainment Agenda, leadership is required from policymakers at the federal, state and institutional levels.

Improving equity in higher-education outcomes will also require a comprehensive approach that recognizes the roles and responsibilities of different stakeholders, the characteristics of the target population and the characteristics of the state and local context. President Obama's January 2015 proposal for tuition-free community college is an example of an approach for increasing higher-education access and attainment that explicitly identifies interrelated roles of the federal government, state governments, higher-education institutions and students. Whether or not this particular proposal is adopted, policymakers should use it to engage in productive dialogue about key underlying questions:

Who should have the opportunity to enroll in and benefit from higher education?

How should the costs be shared among the federal government, state governments, and students and their families, given the countless individual and societal benefits of higher education?

How can the federal government, state governments, colleges and universities, and students and families work together to achieve what should be a shared goal: raising the educational attainment of the nation's population and closing persisting gaps in attainment across groups?

Perna is executive director of the Alliance for Higher Education and Democracy and  James S. Riepe Professor at the Graduate School of Education at the University of Pennsylvania. She is also the co-author, with Joni Finney, of The Attainment Agenda: State Policy Leadership for Higher Education (Johns Hopkins University Press, 2014).