07.22.08

At a cost of $58 million, five elementary and middle schools will expand to pre-K-8, receiving students from the shuttered schools when classes begin in August. An additional 13 will become pre-K-7 this fall and add eighth grade in 2009.

Rhee cites a body of research showing that pre-K-8 students score higher on standardized tests than their middle or junior high school counterparts and benefit socially from skipping the often-wrenching transition that comes with the jump from elementary school. Reduced absenteeism, fewer discipline problems and increased parental involvement are among the other advantages, the studies conclude.

Evidence of pre-K-8's long-term benefits, however, is far from clear-cut. A 2006 study of the Philadelphia school district, which has made a major commitment to pre-K-8, showed that most of the academic gains came in schools with students from higher-income households.