I love teaching. I love getting to know my students, challenging them to think in new ways, and engaging them in a conversation centered around important questions. I love seeing their passion to solve great problems, and I love sharing what I’ve learned to help them solve those problems. That’s why I write blog posts like this one. Last November, for example, I wrote about homelessness. I talked about the homeless Los Angelenos I passed by on my way to the airport. I felt for them. I vowed to help them. But it wasn’t until I started writing this post that it occurred to me that some of them could be my students.

At least 56,000 college students are homeless in the United States today. Some have been found to attend the University of Southern California, where I teach. Just down the road from us, California State University has found that one-tenth of its students is homeless. If true, we are significantly underestimating the problem nationwide, because most of these students don’t tell the federal government that they’re homeless when they apply for federal aid. We really have no idea how high the number goes.

How is this possible?

Let’s start with the fact that room and board at the average public, four-year college costs more than the tuition itself. Next, remind yourself that the student housing isn’t available when school isn’t in session. This makes children from abusive families or without families, even when they get student housing, especially vulnerable; they can’t go home for Christmas like everybody else.

The problem is so severe that college students in one survey were three times as likely to be living in a homeless shelter as the rest of the city’s residents. In another city, 68 percent of homeless youth between the ages of 18 and 21 had attended school that year. Far from the stereotypical portrait of homelessness in America, these kids are smart and studying and striving. And they’re struggling to get to school safe and on time, let alone pass their courses.

They’re not the only ones struggling.

At City University of New York, 42 percent of students were “housing insecure,” with problems ranging from not having enough money to pay rent, to leaving because they felt unsafe in their home, to experiencing foreclosure. In Wisconsin, Sara Goldrick-Rab, one of the country’s leading experts in higher education, surveyed students receiving financial aid and was shocked by what she found. “We expected to hear them tell us that they were having trouble affording their books or buying a laptop,” she said, “but what we heard about was food insecurity; one student told us that she was living in a shelter.”

College is expensive. We all hear the stories about soaring tuition and burdensome loans, and those concerns are well-founded. But they are only part of the picture.

A college career, like everything else in our lives, begins at home, where we study and sleep and have our breakfast before each day of school. An overwhelming body of research has shown that schoolchildren perform poorly and develop slowly when their home environment is stressful or unsafe or unaffordable. Why would we expect it to be any different when these children graduate and go off to college?

This hard reality was an important motivation for why Enterprise Community Partners started its Make Room campaign. The goal of Make Room is to put a spotlight on housing insecurity and galvanize forces to fight to prevent and eliminate it. Great progress has been made, and I’m hopeful that its effectiveness will only grow in the coming months and years. (Full disclosure: I serve on the Enterprise board.)

That campaign aside, when we look at what’s happening out in the field we can see that solutions exist. The state of Washington is partnering with Tacoma Community College to target Housing Choice Vouchers to full-time students who are homeless. The state of California is requiring its colleges to give foster youth priority for housing. Other colleges have hired administrators solely to find and assist homeless students. But, sadly these independent programs are not enough.

The great challenges of our time do not exist in any one silo, but rather at the interstices between them. When I was at HUD, we spoke often about “housing as a platform” and the many ways that housing matters for issues far afield from basic shelter. The problem of housing insecurity for students, with its negative effects, is a classic example of this, and recognizing this reality points to a pathway to systemic success.

Only by creating a dialogue between leaders in both higher education and housing can we solve either problem. Better, more affordable housing will improve education, and better, more affordable education will improve housing.

Once you realize the connection, it’s impossible not to see it everywhere you look. If you do, you’ll see something astonishing: an entire generation that wants so badly to study and learn and make something of themselves that they are willing to make deep sacrifices so that the lack of a secure home does not deter them in the classroom.

They are the reason I teach. They are the future.