On the walls of the classroom were dozens of certificates from the New York State Regents exam, testifying to first-class honors for Corcoran's students.
"We had a girl in this class," Corcoran said. "she was a horrible math student in fifth grade. She cried every Saturday when we did remedial stuff. Huge tears and tears."
At the memory, Corcoran got a little emotional himself. He looked down. "She just emailed us a couple weeks ago. She's in college now. She's in the accounting major."
The story of the miracle school that transforms losers into winners is, of course, all too familiar.
It's the stuff of inspirational books and sentimental Hollywood movies. But the reality of places like KIPP is a good deal less glamorous than that.
To get a sense of what 50 to 60 percent more learning time means, listen to the typical day in the life of a KIPP student.
The student's name is Marita. She is an only child in a single-parent home. Her mother never went to college. The two of them share one-bedroom apartment in the Bronx.
Marita used to go to a parochial school down the street from her home until her mother heard of KIPP.
"When I was in forth grade, me and one of my other friends, Tanya, we both applied to KIPP," Marita said.
"I remember Miss Owens. She interviewed me and the way she was saying made it sound so hard I though I was going to prison. I almost started crying.
And she was like, if you don't want to sign this, you don't have to. But Mom was right there, so I signed it." With that, her life changed.
Keep in mind, while listening to what follows, that Marita is twelve years old.