The 2016 National Teacher of the Year, Jahana Hayes, left — an advocate for greater teacher diversity — pumps her fist as she is acknowledged during a ceremony at the White House.  (Pablo Martinez Monsivais/Associated Press)

The U.S. Education Department, the nation’s two largest teachers unions and Teach For America often do not agree on questions of education policy. But they have found common ground when it comes to the need for a more diverse teaching corps, an issue that they say is critical not only for schools but for the country.

The organizations jointly hosted a national summit on teacher diversity in Washington on Friday, a daylong event meant to call attention to the issue and why it matters.

The problem, they say, is that while diversity among the nation’s K-12 public school students has exploded over the past three decades …

…the teaching force has remained overwhelmingly white.

A growing body of research has documented the ways in which race and ethnicity influence interactions between teachers and students.

Black students, for example, are more likely to be identified as gifted if they are taught by black teachers. Black teachers are more likely to believe that a black student will graduate from high school and go to college than white teachers evaluating the very same black student.

At Friday’s summit, U.S. Education Secretary John King said that students of color would benefit from having more educators and role models who look like them. And white students would benefit from seeing more people of color in leadership positions in their schools.

He pointed to the national debate about criminal justice and policing, driven by recent high-profile killings of black men by white officers, such as in Ferguson, Mo.

“If your first interaction with a person of another race or ethnicity, or someone who speaks a different language, comes as an adult in a situation of incredible crisis and conflict, you’re less likely to be prepared to deal with that well than if you’ve had those experiences early in life,” King said.

“This issue of diversity is really about making our country better,” he said. “We will get closer to our goals of equity and excellence if we have a diverse teaching workforce.”

The federal agency released a report Friday showing that people of color are underrepresented not only in the nation’s classrooms, but in the teacher prep programs that feed classrooms.

King said the problem is not just with recruiting teachers of color but also with retaining them. Some teachers of color leave the classroom for the same reasons that any teacher leaves, including low pay and poor working conditions.

“It’s going to be hard to retain teachers if there’s water dripping from the ceiling and rodents running across the floor,” he said, speaking of the conditions in Detroit schools.

But some teachers of color are driven away by what King called an “invisible tax” — the burden of being the teacher who is always asked to handle diversity concerns at a school, or is always asked to handle the children who are difficult to manage.

Those are often jobs that come without additional support, King said, adding that it’s important for school and school system leaders to remember that “diversity is all of our responsibility.”