In this file photo from 2006, third-grade teacher Marla Wyche opens the "interactive notebook" in her classroom as she prepares to drill students on holidays and people to know. Studies show that minority students can benefit from having minority teachers, but a new study says there are too few of them. (Linda Davidson/The Washington Post)

Persistent achievement gaps among black and Hispanic students have confounded education experts for years. One strategy researchers have found to be successful at narrowing the gaps is a simple one: Employ more minority teachers, who often can forge a better connection with them.

But a new study from the Brookings Institution and the National Council on Teacher Quality identifies several challenges school districts must address in seeking to increase the ranks of minorities leading classrooms, including a leaky recruiting pipeline that could lead to a dearth of qualified candidates lasting decades.

Because few minority college graduates are choosing to become teachers, it is increasingly difficult to recruit minorities into classrooms where they could potentially boost the performance of minority children and increase the pipeline of teacher candidates, according to the study, released Thursday. The authors described it as a cyclical problem that could remain for decades if hiring practices and recruiting efforts do not change significantly. The study suggests there will be minimal improvement as far out as 2060.

The study — from Michael Hansen and Diana Quintero of Brookings and Kate Walsh and Hannah Putman of the NCTQ — notes that while minority children account for half of the nation’s student body in public schools, minority teachers make up just 18 percent of the workforce, creating a significant disparity.

“Given these bleak findings, the chances of success for districts’ laudable goals to build a teaching corps that mirrors their student populations crumble in the face of reality — even looking forward nearly fifty years,” the authors wrote. “While that harsh truth certainly doesn’t excuse districts to give up and resign themselves to a mostly white teaching force, it does suggest that districts must embrace and promote a range of other, more immediately viable solutions.”

There’s ample research showing that black and Hispanic students stand to gain significant advantages if they could work with minority teachers. Studies of elementary school students in Florida, North Carolina and Tennessee indicate that those with teachers of the same race saw their grades improve in math and reading. Similarly, students with teachers of the same race had fewer suspensions and disciplinary issues and better attendance with fewer chronic absences.

Hansen, director of the Brown Center on Education Policy at Brookings, said in an interview that the study aimed to explore the root cause for the low number of minority teachers. The study found that black and Hispanic students generally are not graduating from college at the same rates as white peers and that a tiny percentage of the black and Hispanic students who do graduate want to become teachers.

It is a “systemic pipeline issue,” Hansen said, one that begins even before students reach college.

Hansen said that the problem is self-perpetuating in many ways. Because the number of minority teachers has not grown at the same pace as the number of minority students, it is increasingly difficult to give those students the benefit of having minority teachers. In turn, minority students who might go to college and become teacher candidates aren’t getting that chance.

“We are seeing exactly the results of this vicious cycle,” Hansen said. “Many teachers are being lost along the way before they are even arriving in the HR offices.”

Matthew Di Carlo, a senior research fellow at the Albert Shanker Institute in Washington, said that the new study clearly demonstrates that “there is no question that improving teacher diversity is a formidable challenge.”

Di Carlo said the lack of teacher diversity is an issue that has affected public school education for years and is “not something that will be solved overnight. Progress can be made and should be made and will be made through slow and steady progress, because that’s how education policy works.”