If less time in the classroom is a cause of poor student performance, can adding more time be the cure? This strategy underlies a major effort to fix the nation's worst public schools. Billions of federal stimulus dollars are being spent to expand learning time on behalf of disadvantaged children. And extended learning time (ELT) is being proposed…

The educational achievement and attainment of young people in the United States has been a long-standing issue of concern. While analyses of long-term trend data from the National Assessment of Educational Progress (NAEP) show that students in the United States have made gains in reading and mathematics over the past few decades, a sizeable…