Despite increased public attention to the cost of higher education and student debt, college tuition continues to grow with no sign of plateauing. According to a new report by The Chronicle for Higher Education, the inflation-adjusted cost of one year at Harvard College has jumped more than 31 percent since 1998. Last spring, the College announced that yearly tuition would break $60,000 for the first time in its history.

Of course, these tuition hikes have gone hand in hand with increases in financial aid. In 2014, the University spent $170 million on need-based aid, compared to $73 million in 2004, when the University first launched the Harvard Financial Aid Initiative. The average family now pays $12,000 annually—less than a fifth of Harvard’s sticker price—and the College has projected that more than half of the Class of 2019 would receive financial aid.

But while recipients of aid continue to pay similar amounts to attend Harvard, higher income families are bearing the burden of the tuition hikes. For example, a family earning $250,000 annually, the benchmark just short of qualifying for need-based aid, has seen tuition eat up a significant and increasing portion of its income.

This trend—demanding more and more for tuition with no ceiling in sight—may be unfair to higher income families, especially those that fall just short of receiving aid. But even more troubling is the possibility that increasing tuition alongside financial aid creates a self-reinforcing cycle furthering growth in both categories. This idea is called the Bennett Hypothesis after President Reagan’s former Secretary of Education William Bennett, who proposed it in a 1987 New York Times op-ed. It suggests that generous aid policies enable universities to raise tuition knowing that the aid will soften the increases.

As costs keep rising, this theory continues to gain support. Speaking at the University of Michigan in 2012, President Obama echoed Secretary Bennett’s argument: “It’s not just enough to increase student aid and you can imagine why. We can’t just keep on subsidizing skyrocketing tuition.”

Despite rising costs, studies continue to point to the long-term value of higher education. Tuition growth is not likely to deter students from attending college altogether any time soon. But if tuition at Harvard and other private institutions continues to increase unabated, at a certain point the cost-benefit analysis of attending will simply not add up, particularly for those near the aid threshold.

Given the large amount of aid that colleges like Harvard receive from the federal government, government policies have a key role to play in slowing tuition growth. President Obama has continued to pursue ideas in this area, as have presidential contenders like Hillary Clinton, but more decisive action on this front is clearly needed.

More locally, Harvard should hold itself accountable for keeping tuition down. This goal is especially crucial as Harvard aims to attract students from more diverse backgrounds. The University, cushioned by its $37 billion endowment, must commit itself to bringing tuition growth under control. With the resources to lead on this issue, we have few excuses for not aggressively pursuing solutions.