PHILADELPHIA — More than two dozen of the city's worst schools are being put under the microscope as education officials begin assessing which ones will be essentially shut down and reopened next year with new staffs and new academic focus.

The "Renaissance Schools" initiative seeks to reinvigorate the poorest-performing schools that have continuously failed to educate district students, nearly half of whom cannot read or do math at grade level.

"I am so excited," Superintendent Arlene Ackerman said today. "We're really trailblazing here."

It's an approach supported by President Barack Obama, who has a goal of turning around 5,000 failing schools across the U.S. in the next five years. About $3.5 billion has been set aside for the effort this year through federal stimulus legislation.

Officials in cities including Chicago and Hartford, Conn., have already overhauled several schools. U.S. Education Secretary Arne Duncan, a former Chicago schools chief, is widely known for reinventing several schools there through complete staff overhauls.