Dexter Hannibal is a first-year teacher at Brooklyn Democracy Academy, a high school in Brownsville for students who've fallen behind. Sixty percent are boys of color. 

"It's important for them to be able to see someone who looks like them and maybe has some of the shared life experiences they've had," Hannibal said. "For most of my students, they are immigrants and come from immigrant backgrounds. I'm also an immigrant, so I had to learn the history the way they are learning the history."

Research shows it's good for kids to have teachers who look like them. Black boys from low-income households are less likely to drop out and more likely to apply to college if they've had a black male teacher. But while 43 percent of city public school students are boys of color, only 8 percent of teachers are black, Asian or Hispanic men. 

"We're doing damage both to the black students, for whom it has a negative impact on their educational outcomes, but it does damage to all students with whom it has an impact on how they view the world," said Deputy Mayor Richard Buery.

Two years ago, Mayor Bill de Blasio made what sounded like a bold promise - the city would recruit 1,000 men of color to teach by 2017. He set aside $16.5 million for the effort, which paid for radio and subway ads, sending recruiters to historically black colleges, and working with Teach for America to identify potential hires.

The city says it's almost reached the goal. Three hundred and fifty male teachers of color have been hired. Five hundred and fifty more are in the pipeline.

But at 8 percent, the proportion of black, Asian and Hispanic men in the teaching force today is the same as when the recruitment effort began.

"We're seeing lower retention rates, more likely not to stay with the profession. And that's gotten worse and worse in recent years, as some of the teachers who have been in the sytem for a long time are hitting retirement age," Buery said.

Without the recruitment effort, the percentage of men of color would likely have dropped. Still, it remains stubbornly out of sync with the demographics of the students, many of whom still don't have teachers who look like them.