You’re a high school senior and you’ve just been accepted to New York University, your dream school. You and your parents have carefully calculated what getting your bachelor’s degree is going to cost you.

Or so you thought. It turns out NYU covers nearly three-quarters of the financial need for incoming freshman, but just 60 percent of need over the course of a four-year education. And it’s not just NYU. At Sarah Lawrence College, for instance, the price students pay after subtracting grant aid increased by $14,000 over the last four school years. The college now asks families earning $30,000 or less to pay nearly $23,000 for one year of school.

These examples are far from unique. Few college students pay the published price for their college experience. Grant aid from the federal government, states, and school, in the form of scholarships rewarding academic achievement or need-based aid for low- and moderate-income students, sets the price each student will pay. But there is no guarantee that extra help from the college will be stable over four years. This means the price may fluctuate for many students over the course of their education.

Perhaps more importantly, there is no guarantee that the combination of federal and institutional aid will result in an affordable price tag for low- and moderate-income students, even in their first year of school, when colleges are typically most generous. For example, in 2013-14, Catholic University in Washington, D.C., charged the neediest students, whose families earn less than $30,000, an average net price of $29,820 a year—even after grants and scholarships brought down the published price. Given the resources of these students, this amount can hardly be considered “affordable,” even if prices were stable over four years. And while Catholic represents an extreme, it is hardly alone. The median cost of a year at a four-year public or private college for a family making less than $30,000 is $11,364, even after help from the university, state, and the federal government—still unaffordable by almost any measure.

These two major pricing problems have created a higher-education system characterized by uncertainty and instability for families. Middle-class students deal with the fear that tuition rates could spike or crucial grant dollars could disappear. And the hopes and dreams of low-income students are often crushed when thousands of dollars in federal assistance still aren’t enough to bring the price tag within reach.

We propose that the cost of a college education be clear and stable over the course of a student’s education, and that it should not consign the student to a lifetime of burdensome debt. We need a system in which colleges and universities are required to provide students with transparency and certainty regarding exactly how much their education will cost. Students deserve to know going in what they will pay out of pocket for their entire college career. And for low- and middle-income students, schools should commit to charging families a reasonable contribution to the cost of education, taking into consideration federal aid.

The federal student aid programs are a massive investment in our nation’s higher-education system. Each year they distribute almost $120 billion in grants and loans to help millions of students attend college. While crucial for students, this money comes with few strings attached for colleges. Despite the fact that schools receive billions in federal dollars, they are under no obligation to guarantee students an affordable or high-quality education.

Making financial aid effective means making financial aid and college pricing more predictable for middle-income families, and that starts with the process of determining aid eligibility. When families apply for federal aid, the government calculates their “expected family contribution,” an estimate  that helps approximate what they can expect to pay for school out of pocket. But the estimate is just that—an estimate. The figure is far from binding, and many families end up spending much more than the federal estimates. Congress should require institutions to charge a reasonable approximation of that estimate.

Another crucial task is establishing affordability requirements for the lowest-income students. Today, even students who receive the most federal grant aid have no guarantee from their colleges that the assistance they receive will be enough for them to afford college without taking on thousands or tens of thousands in loan debt. In fact, these low-income students on average still have to pay nearly 75 percent of their annual family income to afford a year of college. This has to change.

These changes are critical to ensuring that taxpayer dollars are used as efficiently as possible. They’re also critical to ending longstanding bad behavior by schools, which drives up the cost for all families. For example, pricing gimmicks—such as offering a hefty financial aid package for freshman year, then jacking up prices and dropping aid amounts once a student is already enrolled, as in the NYU example above—hurt families at every income level. These pricing maneuvers make it almost impossible for students and families to judge college value, since they don’t know how much they will pay for multiple years of education.

These dramatic pricing swings are bad in two ways. First, they cause some students to significantly overestimate the price of college, get discouraged, and never apply because it feels out of reach. Second, for those who do go, unexpected price spikes or decreases in financial aid place them at significant risk of dropping out or defaulting if their debt burden becomes overwhelming. Students who take out loans to pay for college but never finish school are three times more likely to default than those who graduate. And the cost of these defaults to society lingers for decades, as these borrowers have a harder time contributing to the economy by working and buying homes.

Adding transparency and affordability requirements to the student aid system wouldn’t be such a radical change. These types of controls are already in place for other critical government-subsidized services, such as health care or housing. The goal of the federal financial aid programs is to make college affordable. But the current structure gets it only half right. The federal government provides the money, but it never ensures that those benefits have any actual purchasing power. It’s time to give students certainty about what they can expect to pay for a college education—and about whether they can afford that education—before they set foot on campus.