Starting last week, more than 15,000 children in school uniforms appeared on city streets. Public schools open on Sept. 7 but halfway through August, the Success Academy charter school network began the new academic year. 

"It was awesome. We got to do a lot of fun things," said one Success student.

A longer school year and a longer school day - the charter network says that's part of its formula for success. Tuesday, state test scores highlighted the network's position as an academic - and test taking - powerhouse.

Overall, Success students, most of whom are black, Hispanic and poor, outperformed students in the city's public schools -- and even in posh suburbs like Scarsdale and Chappaqua. 

Ninety-five percent of Success students passed the math exam, compared to 38 percent citywide.

Eighty-four percent passed the reading exam, compared to 41 percent across the city. 

"We focus a lot on thinking and making sure kids are being critical thinkers. We focus a lot on training our teachers. We focus a lot on parental investment. We focus a lot on making sure our kids are well rounded," said Bed-Stuy Middle School Principal Rishabh Agarwal.

They also focus a lot on the exams. Each year, the network holds a huge motivational rally celebrating students with high practice test scores. This year, it was held in Radio City Music Hall.  

"We have to do a few tests every day. It's from January though May or June," said one Success student.

His younger brother, a third grader, says teachers have already brought it up.

"They started telling me we are doing big tests this year and it's going to be more serious about the tests," noted the Success student.

Critics say Success benefits from private donations and stacks the deck pushing out kids with behavior problems or uncooperative parents and not taking new students after 4th grade. The schools are known for high suspension rates, even among young students.

Still, the principal of Success' Bed-Stuy Middle School says those factors cannot explain the superior testing results compared to the public schools. 

"The gap is so, so wide, that we're not talking about a percent or two, we're talking about a 50, 60, 70 percent pass rate," Agarwal said.