The charter school revolution of the last few decades has transformed the conversation about education reform in America's large cities, including New York. Data suggests that simply organizing a school through a charter agreement does not guarantee greater student achievement. But some charter schools have used their flexibility to test innovations that seem to make a measurable difference. And as Citizen Schools' New York Executive Director Kathrine Mott writes in an op-ed in Crain's New York Business, the public school system overall should look to what high-performing charters have done in deciding what resources to invest in.

One such variable is the length of the school day....

"Charter schools and traditional public schools alike have implemented this approach in New York City," she writes. "We are already seeing evidence that this can improve academic outcomes."

With the right investment from policy makers, public schools can implement the innovations that work. Schools that have formed partnerships with non-profits like Citizen Schools, for instance, have been able to extend their learning time by several hours each day, and--more importantly--enable students to improve at rates comparable to the highest performing charter schools.

"There is a heated debate in New York City about how public resources are allotted to charter schools," she writes. "Regardless of where one stands on this issue, we can find common ground when it comes to bringing some of the innovative aspects of charter schools into the city's public schools. A good place to start is with a longer school day."

Read the full op-ed, A Charter Lesson To Lift Public Schools, at Crain's New York.