Pre-kindergarten children at public charter school.

WASHINGTON, D.C., MARCH 31, 2011. Pre-kindergarten children attend classes at LEAP Academy Early Childhood School (PreK3 Ð Kindergarten) at KIPP DC. KIPP (Knowledge is Power Program) DC is a network of high-performing, public charter schools in Washington D.C., which mostly serves the city�s under-resourced communities. Dozens of D.C. charters are offering preschool and prekindergarten, a rapidly growing trend that marks a distinct shift in the focus of the charter-school movement. The growth arises from the idea that students who start school early will make bigger achievement gains. (Photo by ASTRID RIECKEN For The Washington Post via Getty Images)

Pre-kindergarten children at public charter school.