Researchers analyzing Chicago's remedial education programs found that summer school substantially increased academic achievement among third graders, but not sixth graders. Also, contrary to conventional wisdom and prior research, grade retention increased achievement for third grade students, but had little effect on math achievement for sixth grade students.

The summer of 2000, Caitlin Johnson volunteered in a language arts summer school class for 6th graders in Alexandria, Virginia, she left convinced that helping kids become confident writers is a critical job—and a tough one.