Mount Vernon Woods Elementary School kindergarten teacher Cynthia Walker guides her future charges during the orientation for incoming students and their families on May 5, 2015. (Tin Nguyen/Fairfax County Times)

John King is U.S. education secretary.

One of my top priorities as education secretary is to help our public schools serve the needs of our increasingly diverse students so that they have the opportunity to pursue the American dream and use their talents to help our nation tackle some of its most difficult problems.

To achieve this goal, we need a teaching force that is as diverse as our students. More and more research shows that diversity isn’t just a nicety — it’s a real contributor to better outcomes in our schools, workplaces and communities. But while students of color are now a majority in our schools, teachers of color make up only 18 percent of their faculties. Unless we do something as a country, demographic projections show that this mismatch is likely to get worse.

To address this, we need to encourage a wider array of young people to consider teaching as a career, prepare them to meet the learning needs of their diverse students and actively recruit and hire them. But we also must do more to ensure that, once hired, they will stay.

Research conducted recently by the American Federation of Teachers found that, while more teachers of color are being hired than in the past, they also are leaving the profession more quickly than white teachers.

Improved compensation and working conditions can help address this, of course. But one factor in teachers’ decisions to leave deserves special attention: the “invisible tax.”

According to some African American male teachers, the “invisible tax” is imposed on them when they are the only or one of only a few nonwhite male educators in the building. It is paid, for example, when these teachers, who make up only 2 percent of the teaching force nationally, are expected to serve as school disciplinarians based on an assumption that they will be better able to communicate with African American boys with behavior issues.

It is also paid when they have to be on high alert to prepare their students for racism outside of school. “Every time I take my students to an engineering competition, or to speak with industry partners, or to tour colleges, I have to have the code-switching talk,” explained Harry Preston, an African American physics teacher in Baltimore. “That is a mental tax I personally pay as an educator.”

And it is paid when teachers of color are seen as the experts on any question of cultural diversity.

The tax takes a toll on teachers’ time. Building and maintaining relationships with students across an entire school adds to their already busy schedules as teachers. It also takes an emotional toll. Often, the students whom black male teachers are expected to help have serious needs beyond what any individual teacher can remedy. That leads to burnout.

John B. King Jr. thanks President Obama after being named U.S. secretary of education. (The White House/ Youtube)

Sharif El-Mekki, principal of the Mastery Charter School’s Shoemaker campus in Philadelphia, has noted that the African American teachers he speaks with are of two minds about these extra duties. “They feel honored and appreciated that they are asked,” he said, “but when so many different people are asking them for help, it becomes a burden.”

Such conversations prompted El-Mekki to found the Fellowship, which seeks to inspire more men of color in Philadelphia to see teaching as a means of achieving social justice. The Fellowship has hosted several Black Male Educator Convening events to provide peer support and guidance.

At these gatherings, teachers express a desire to be seen as experts for their mastery of subjects they teach or for their innovative teaching, as well as for any special connection they might have to students. They want to be seen as a resource for white colleagues to learn how to better support their African American students. “If everyone was asked to improve their relationships with these students . . . it would feel empowering,” El-Mekki said.

I encourage school and district leaders to work with their teachers and other staff members to develop a vision for how to make their campuses more inclusive by adopting proactive hiring processes, providing professional support, using a multicultural curriculum and offering cultural competence workshops for everyone. The burden to end this tax shouldn’t fall only to the people already paying it.

We have strong evidence that students of color benefit from having teachers who are positive role models, as well as from the changes in classroom dynamics that result. Teachers of color often have higher expectations for students of color, are more likely to use culturally relevant teaching practices, are more likely to confront racism in their lessons and, yes, also serve as advocates.

But it’s also important for our white students to see teachers of color in leadership roles in their classrooms and communities. Breaking down negative stereotypes helps all students learn to live and work in a multiracial society.

Ultimately, the work we can do together to create opportunity for all students will determine not only the kind of economy we have and the kind of people we will be, but also whether we will become the nation we ought to be.