A study in Kenya by Michael Kremer, a Harvard economist, examined six different approaches to improving educational performance, from providing free textbooks to child-sponsorship programs. The approach that raised student test scores the most was to offer girls who had scored in the top 15 percent of their class on sixth-grade tests a $19 scholarship for seventh and eighth grade (and the glory of recognition at an assembly). Boys also performed better, apparently because they were pushed by the girls or didn't want to endure the embarrassment of being left behind.